JP2014088550A - Metal particle-dispersed body, article and sintered film using the metal particle-dispersed body, and method for producing the sintered film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal particle-dispersed body having low viscosity and excellent dispersibility and dispersion stability, and in which the settling of metal particles is suppressed.SOLUTION: The metal particle-dispersed body comprises metal particles, a dispersant and a solvent. The metal particles include one or more kinds selected from a group consisting of Au, Ag, Cu, Ni, Pt, Pd, Mo, Al, Sb, Sn, Cr, La, In, Ga and Ge, and also, the dispersant being a graft copolymer having a constitutional unit represented by formula (I) and a constitutional unit represented by formula (II), and in which at least a part of a nitrogen site included in the constitutional unit represented by formula (I) and at least one kind selected from the group consisting of halogenated carbon hydride, an acid phosphorous compound represented by formula (V) and a sulfonic acid compound represented by formula (VI) form a salt.

Description

  The present invention relates to a metal particle dispersion, an article using the metal particle dispersion, a sintered film, and a method for producing the sintered film.

  Fine metal particles having a particle size of several nanometers to several tens of nanometers exhibit various physical and chemical characteristics that are different from conventional metal materials, so conductive pastes, transparent conductive films, light shielding filters, Expected to be applied in a wide range of fields such as chemical sensors, catalysts, antibacterial materials, light guide members, gas barrier materials, light scattering / reflecting members, light diffusing members, photosensitive materials, photoelectric conversion elements, fluorescent materials, and coloring materials. . The metal particles can be made into an ink or paste-like metal particle dispersion by dispersing in a solvent.

  For example, metal particle dispersions in which metal particles made of metal oxides such as ITO (tin-doped indium oxide) and ATO (tin-doped antimony oxide) are uniformly dispersed in a matrix material are used for applications such as transparent conductive films and heat ray shielding films. ing. In this case, when metal particles with a particle size larger than several tens of nanometers are used, visible light is scattered and appears turbid, but by using metal particles with a particle size smaller than several tens of nanometers, light scattering is suppressed. It is expected that an optical material having a high value will be obtained.

In addition, it is known that the melting point of the metal particles dramatically decreases as the particle size is reduced. This is because the specific surface area of the particles increases and the surface energy increases as the particle size of the metal particles decreases. If this effect is utilized, in the technique of printing a pattern directly on a base material using a metal particle dispersion and forming a circuit pattern, sintering of metal particles can proceed at a lower temperature than in the past. Compared with conventional photoresist methods, productivity is dramatically improved, and it is expected that circuit formation by printing will be possible even for resin substrates with low heat resistance, which have been difficult to use in the past. Has been.
Thus, fine metal particles are widely used as metal particle dispersions, and metal fine particle dispersions having better dispersibility and dispersion stability are desired.

  Patent Document 1 discloses an antireflection film containing specific metal oxide fine particles, a nonionic organic dispersant, a binder, and an organic solvent as a technique excellent in dispersion stability of metal oxide fine particles. A coating composition is described.

Patent Document 2 discloses a protective colloid containing an organic compound having a carboxyl group and a polymer dispersant as an ink composition capable of printing or printing characters and images with excellent metallic luster by an inkjet printing method. The use of coated metal colloidal particles is described.
However, the methods of Patent Documents 1 and 2 require a large amount of a dispersant when dispersing a high concentration of metal particles, and further improvement in dispersibility has been demanded.

Patent Document 3 describes a metal fine particle dispersion containing specific metal fine particles, a polymer dispersant having a specific polyester skeleton, and a dispersion medium.
According to Patent Document 3, it is described that the specific polymer dispersant has a high effect on the dispersibility of the metal fine particles and is easily volatilized in a subsequent sintering step. However, as shown in a comparative example described later, in the method of Patent Document 3, the storage stability of the metal fine particle dispersion is not sufficient, and the precipitation of the metal particles may be observed after storage for a certain period.

JP 2005-272755 A JP 2009-227736 A International Publication No. 2011/040189 Pamphlet

  As described above, a metal particle dispersion in which fine metal particles are uniformly dispersed is desired. However, since metal particles generally have a high specific gravity and are likely to settle, it has been a very difficult task to obtain a dispersion having high dispersibility and dispersion stability. Furthermore, it is difficult to prepare a dispersion having better dispersibility and dispersion stability as the particle size of the metal particles is smaller.

  The present invention has been made under such circumstances, the metal particle dispersion excellent in dispersibility and dispersion stability and suppressed sedimentation of metal particles, and the metal particle dispersion according to the present invention, Alternatively, an object is to provide an article including a coating film, a molded body, or a sintered film of a composition containing the metal particle dispersion.

As a result of intensive studies to achieve the above object, the present inventors have obtained the knowledge that the use of specific metal particles in combination with a specific dispersant results in excellent dispersibility and dispersion stability. .
The present invention has been completed based on such knowledge.

The metal particle dispersion according to the present invention contains metal particles, a dispersant, and a solvent,
The metal particles are metal particles including one or more selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, and germanium. Yes, and
The dispersant has a structural unit represented by the following general formula (I) and a structural unit represented by the following general formula (II), and is included in the structural unit represented by the general formula (I). At least a part of the nitrogen moiety selected from the group consisting of a halogenated hydrocarbon, an acidic phosphorus compound represented by the following general formula (V), and a sulfonic acid compound represented by the following general formula (VI) One type is a graft copolymer in which a salt is formed.

(In general formula (I), A is a direct bond or a divalent linking group, R ¹ is a hydrogen atom or a methyl group, Q is a group represented by the following general formula (Ia), or a substituted group. Represents a nitrogen-containing heterocyclic group which may have a group and can form a salt.)

(In general formula (Ia), R ² and R ³ each independently represent a hydrocarbon group that may contain a hydrogen atom or a hetero atom, and R ² and R ³ may be the same or different from each other. May be.)

(In general formula (II), R ^{1 ′} is a hydrogen atom or a methyl group, L is a direct bond or a divalent linking group, and Polymer is represented by the following general formula (III) or general formula (IV). (Represents a polymer chain having at least one structural unit.)

(General formula (III) and the general formula (IV), ^{R 4} is a hydrogen atom or a methyl group, ^{R 5} is a hydrocarbon group, a cyano ^{group, - [CH (R 6)} -CH (R 7) - _{^{O] x -R 8, - [}} (CH 2) y -O] z -R 8, - [CO- (CH 2) y -O] z -R 8, -CO-O-R 9 or -O- It is a monovalent group represented by CO—R ^10. R ⁶ and R ⁷ are each independently a hydrogen atom or a methyl group.
R ⁸ is a hydrogen atom, a hydrocarbon group, a monovalent group represented by —CHO, —CH ₂ CHO, or —CH ₂ COOR ¹¹ , and R ⁹ is a hydrocarbon group, a cyano group, — [CH (R ⁶ ) —CH (R ⁷ ) —O] _x —R ⁸ , — [(CH ₂ ) _y —O] _z —R ⁸ , or — [CO— (CH ₂ ) _y —O] _z —R ⁸ A monovalent group. R ¹⁰ is an alkyl group having 1 to 18 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The hydrocarbon group may have a substituent.
m represents an integer of 1 to 5, and n and n ′ represent an integer of 5 to 200. x is an integer of 1 to 18, y is an integer of 1 to 5, and z is an integer of 1 to 18. )

(In General Formula (V) and General Formula (VI), R ^a and R ^{a ′} are each independently a hydrogen atom, a hydroxyl group, a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O]. _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^{a ″} is a monovalent group. R ^{a ″} represents a hydrocarbon group, — [ _{^{CH (R c) -CH (R}} d) -O] s -R e, - [(CH 2) t -O] u -R e, -C (R f) (R g) -C (R h) It is a monovalent group represented by (R ⁱ ) —OH or —CH ₂ —C (R ^j ) (R ^k ) —CH ₂ —OH.
R ^b is a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^b. It is a monovalent group represented by ^' . R ^{b ′} is a monovalent group represented by a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , or — [(CH ₂ ) _t —O] _u —R ^e. It is the basis of.
R ^c and R ^d are each independently a hydrogen atom or a methyl group, and R ^e is a monovalent group represented by a hydrogen atom, a hydrocarbon group, —CHO, —CH ₂ CHO, or —CH ₂ COOR ^1. And R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ^f , R ^g , R ^h , R ⁱ , R ^j and R ^k are each independently a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded to at least one of an ether bond and an ester bond. R ^f and R ^h may be bonded to each other to form a ring structure. When the above cyclic structure is formed, it may have a substituent R ⁿ , and R ⁿ is a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded by at least one of an ether bond and an ester bond. It is.
In R ^a , R ^{a ′} and R ^b , each hydrocarbon group may have a substituent.
s is an integer of 1 to 18, t is an integer of 1 to 5, and u is an integer of 1 to 18. )

  In the metal particle dispersion of the present invention, the average primary particle size of the metal particles is preferably 5 to 200 nm.

  Moreover, this invention provides the articles | goods containing the coating film, the molded object, or the sintered film of the composition containing the metal particle dispersion which concerns on the said this invention, or a metal particle dispersion.

  According to the present invention, a metal particle dispersion excellent in dispersibility and dispersion stability, in which sedimentation of metal particles is suppressed, and the metal particle dispersion according to the present invention, or a composition containing the metal particle dispersion, are provided. Articles including a coating, a molded body, or a sintered film can be provided.

FIG. 1 is a schematic view showing an example of an article according to the present invention. FIG. 2 is a schematic view showing another example of an article according to the present invention. FIG. 3 is a schematic view showing another example of an article according to the present invention.

Hereinafter, the metal particle dispersion and the article according to the present invention will be described.
In the present invention, light includes electromagnetic waves having wavelengths in the visible and invisible regions, and further includes radiation, and the radiation includes, for example, microwaves and electron beams. Specifically, it means an electromagnetic wave having a wavelength of 5 μm or less and an electron beam. In the present invention, (meth) acryl means either acryl or methacryl, and (meth) acrylate means either acrylate or methacrylate.

[Metal particle dispersion]
The metal particle dispersion according to the present invention contains metal particles, a dispersant, and a solvent,
The metal particles are metal particles including one or more selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, and germanium. Yes, and
The dispersant has a structural unit represented by the following general formula (I) and a structural unit represented by the following general formula (II), and is included in the structural unit represented by the general formula (I). At least a part of the nitrogen moiety selected from the group consisting of a halogenated hydrocarbon, an acidic phosphorus compound represented by the following general formula (V), and a sulfonic acid compound represented by the following general formula (VI) One type is a graft copolymer in which a salt is formed.

(In general formula (I), A is a direct bond or a divalent linking group, R ¹ is a hydrogen atom or a methyl group, Q is a group represented by the following general formula (Ia), or a substituted group. Represents a nitrogen-containing heterocyclic group which may have a group and can form a salt.)

(In general formula (Ia), R ² and R ³ each independently represent a hydrocarbon group that may contain a hydrogen atom or a hetero atom, and R ² and R ³ may be the same or different from each other. May be.)

(In general formula (II), R ^{1 ′} is a hydrogen atom or a methyl group, L is a direct bond or a divalent linking group, and Polymer is represented by the following general formula (III) or general formula (IV). (Represents a polymer chain having at least one structural unit.)

(General formula (III) and the general formula (IV), ^{R 4} is a hydrogen atom or a methyl group, ^{R 5} is a hydrocarbon group, a cyano ^{group, - [CH (R 6)} -CH (R 7) - _{^{O] x -R 8, - [}} (CH 2) y -O] z -R 8, - [CO- (CH 2) y -O] z -R 8, -CO-O-R 9 or -O- It is a monovalent group represented by CO—R ^10. R ⁶ and R ⁷ are each independently a hydrogen atom or a methyl group.
R ⁸ is a hydrogen atom, a hydrocarbon group, a monovalent group represented by —CHO, —CH ₂ CHO, or —CH ₂ COOR ¹¹ , and R ⁹ is a hydrocarbon group, a cyano group, — [CH (R ⁶ ) —CH (R ⁷ ) —O] _x —R ⁸ , — [(CH ₂ ) _y —O] _z —R ⁸ , or — [CO— (CH ₂ ) _y —O] _z —R ⁸ A monovalent group. R ¹⁰ is an alkyl group having 1 to 18 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The hydrocarbon group may have a substituent.
m represents an integer of 1 to 5, and n and n ′ represent an integer of 5 to 200. x is an integer of 1 to 18, y is an integer of 1 to 5, and z is an integer of 1 to 18. )

(In General Formula (V) and General Formula (VI), R ^a and R ^{a ′} are each independently a hydrogen atom, a hydroxyl group, a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O]. _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^{a ″} is a monovalent group. R ^{a ″} represents a hydrocarbon group, — [ _{^{CH (R c) -CH (R}} d) -O] s -R e, - [(CH 2) t -O] u -R e, -C (R f) (R g) -C (R h) It is a monovalent group represented by (R ⁱ ) —OH or —CH ₂ —C (R ^j ) (R ^k ) —CH ₂ —OH.
R ^b is a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^b. It is a monovalent group represented by ^' . R ^{b ′} is a monovalent group represented by a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , or — [(CH ₂ ) _t —O] _u —R ^e. It is the basis of.
R ^c and R ^d are each independently a hydrogen atom or a methyl group, and R ^e is a monovalent group represented by a hydrogen atom, a hydrocarbon group, —CHO, —CH ₂ CHO, or —CH ₂ COOR ^1. And R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ^f , R ^g , R ^h , R ⁱ , R ^j and R ^k are each independently a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded to at least one of an ether bond and an ester bond. R ^f and R ^h may be bonded to each other to form a ring structure. When the above cyclic structure is formed, it may have a substituent R ⁿ , and R ⁿ is a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded by at least one of an ether bond and an ester bond. It is.
In R ^a , R ^{a ′} and R ^b , each hydrocarbon group may have a substituent.
s is an integer of 1 to 18, t is an integer of 1 to 5, and u is an integer of 1 to 18. )

  The metal particle dispersion according to the present invention is a combination of the specific metal particles and the specific dispersant, which is excellent in dispersibility and dispersion stability and suppresses precipitation of the metal particles. . Further, the metal particle dispersion of the present invention can be a low-viscosity dispersion.

Although there is an unexplained part as an action that exhibits the specific effect as described above by the specific combination, it is estimated as follows.
Conventionally, metal particle dispersions have a problem that the metal particles settle out during storage because the specific gravity of the metal particles is larger than that of each component in the dispersion.
The metal particle dispersion of the present invention has, as a dispersant, a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II), and represented by the general formula (I). A graft copolymer in which at least a part of a nitrogen moiety contained in the structural unit and at least one selected from the group consisting of a halogenated hydrocarbon, a specific acidic phosphorus compound, and a specific sulfonic acid compound form a salt. By dispersing the metal particles using the polymer, it is presumed that the salt-forming site in the dispersant that becomes insoluble in the solvent is stabilized by strongly adsorbing on the surface of the metal particles. Moreover, since the structural unit represented by general formula (II) which a dispersing agent has has a polymer chain, it is excellent in the solubility to a solvent. For this reason, since the specific dispersant surrounds the metal particles and is stably present in the solvent, the metal particles are less likely to aggregate, have excellent dispersibility and dispersion stability, and the metal particles settle. It is presumed that this can also be suppressed.
Since the metal particle dispersion according to the present invention is excellent in the dispersibility and dispersion stability of the metal particles as described above, it is possible to keep the content ratio of the dispersant to the metal particles low compared to the conventional case. Become. Therefore, it is possible to obtain a metal fine particle dispersion having a low viscosity, and when the metal particle dispersion is fired to form a metal film, there is an advantage that there is little residual organic component after sintering.
In the present invention, the specific indication of low viscosity is that the viscosity of the metal particle dispersion is 10 mPa · s or less, and preferably 3 mPa · s or less. Such a low-viscosity metal fine particle dispersion can also be suitably used as an inkjet composition.

Moreover, the metal particle dispersion for forming a sintered film according to the present invention contains metal particles, a dispersant, and a solvent.
The metal particles include one or more metals selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, zinc, and germanium. Particles, and
The dispersant has a structural unit represented by the following general formula (I) and a structural unit represented by the following general formula (II), and is included in the structural unit represented by the general formula (I). At least a part of the nitrogen moiety selected from the group consisting of a halogenated hydrocarbon, an acidic phosphorus compound represented by the general formula (V), and a sulfonic acid compound represented by the general formula (VI) One type is a graft copolymer in which a salt is formed.

(In general formula (I), A is a direct bond or a divalent linking group, R ¹ is a hydrogen atom or a methyl group, Q is a group represented by the following general formula (Ia), or a substituted group. Represents a nitrogen-containing heterocyclic group which may have a group and can form a salt.)

(In general formula (Ia), R ² and R ³ each independently represent a hydrocarbon group that may contain a hydrogen atom or a hetero atom, and R ² and R ³ may be the same or different from each other. May be.)

(In General Formula (II), R ^{1 ′} is a hydrogen atom or a methyl group, L is a direct bond or a divalent linking group, and Polymer is at least one structural unit represented by the following General Formula (III). Represents a polymer chain having.)

(In General Formula (III), R ⁴ is a hydrogen atom or a methyl group, and R ⁵ is a branched alkyl group having 3 to 18 carbon atoms or a monovalent group represented by —CO—O—R ⁹ . R ⁹ is a branched alkyl group having 3 to 18 carbon atoms, and n is an integer of 5 to 200.)

The metal particle dispersion of the present invention contains at least metal particles, a dispersant, and a solvent, and may contain other components as necessary as long as the effects of the present invention are not impaired. Is.
Hereinafter, each component of the metal particle dispersion of the present invention will be described in detail in order.

<Metal particles>
The metal particles used in the present invention include at least one selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, and germanium. It is a metal particle containing. In the present invention, the metal particles include alloy particles and metal compound particles in addition to metal particles. In addition, for example, one particle may contain one or more of a metal, an alloy, and a metal compound so that the surface of the metal particle is oxidized to form a metal oxide. is there. Typically, one or more metals, alloys selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, and germanium, And metal particles that are one or more of metal compounds.
In the sintered film forming application, the metal particles used in the present invention are made of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, zinc, and germanium. It is a metal particle containing 1 or more types selected from a group.
As the type of metal, a material having conductivity, antibacterial properties, heat ray shielding properties, and the like can be appropriately selected depending on applications. In addition, when the metal particle dispersion of the present invention is formed into a metal film by firing or the like, the metal film includes at least one of a metal, an alloy, and a metal compound that exhibits conductivity, antibacterial properties, heat ray shielding properties, and the like. What is necessary is just to select suitably.
Examples of the conductive metal include gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, indium, gallium, and germanium. Among these, gold, silver, copper , Nickel and the like are preferable from the viewpoint of conductivity. Silver and copper are mentioned as a metal which has antibacterial property. Examples of the metal having good heat ray shielding properties include silver, copper, ITO (tin-doped indium oxide), ATO (antimony-doped tin oxide), and lanthanum hexaboride. Here, the heat ray shielding property includes heat ray absorbability and heat ray reflectivity.

Examples of the metal compound include metal oxide, metal hydroxide, metal sulfide, metal selenide, metal telluride, metal nitride, metal phosphide, metal boride, metal silicide, metal carbide, and metal chloride. Thing etc. are mentioned. When a metal film is formed by firing, a metal film that is decomposed during firing to become a metal is preferable. Examples of the metal compound having silver include silver oxide. Moreover, as a metal compound which has copper, copper oxides, such as cuprous oxide, cupric oxide, and these mixtures, etc. are mentioned, for example.
Examples of the alloy include a copper-nickel alloy and a silver-palladium alloy.

Moreover, as a metal compound which has copper, the metal compound containing the following (i), (ii), and (iii) is used suitably for a sintered film formation use.
(I) copper,
(Ii) one or more selected from the group consisting of indium, gallium, zinc, tin, and aluminum,
(Iii) One or more selected from the group consisting of sulfur, selenium, and tellurium As the metal compound containing the above (i), (ii), and (iii), specifically, CIS (Cu-In- Examples thereof include Se) -based compounds or CIGS (Cu-In-Ga-Se) -based compounds, CZTS (Cu-Zn-Sn-Se) -based compounds, and CuSbSe. More specifically, CuAlS ₂ , CuGaS ₂ , CuInS ₂ , CuAlSe ₂ , CuGaSe ₂ , CuInSe ₂ (CIS), Cu (In _1-x Ga _x ) Se ₂ (CIGS), Cu (In _1-x Al _x). ) Se ₂ , Cu (In _1-x Ga _x ) (S, Se) ₂ , CuSbS ₂ , Cu ₂ SbS ₃ , Cu ₂ SnSe ₃ , CuZnSnS ₂ , Cu (In _1-x Ga _x ) Te ₂ CuInS ₂ , CuInSe ₂ (CIS), Cu (In, Ga) S ₂ , Cu (In, Ga) Se ₂ (CIGS), Cu ₂ ZnSn (S, Se) ₂ are particularly preferred. A sintered film of metal particles containing the metal compound is suitably used, for example, as a photoelectric conversion semiconductor film.

A metal particle can be used individually by 1 type or in combination of 2 or more types among the metal particles containing 1 or more types of the said metal, an alloy, and a metal compound.
For example, in a sintered film forming application, for example, one or more types selected from the group consisting of copper particles, indium, gallium, zinc, tin, and aluminum, and one type selected from the group consisting of sulfur, selenium, and tellurium. One or more selected from the group consisting of copper, indium, gallium, zinc, tin, and aluminum, and sulfur, selenium, In addition, a dispersion in which two or more metal compound particles including at least one selected from the group consisting of tellurium are combined and mixed may be used.

  What is necessary is just to select suitably the preparation method of the said metal particle from a conventionally well-known method. For example, a physical method of pulverizing metal powder by mechanochemical method, etc .; chemical dry method such as chemical vapor deposition method (CVD method), vapor deposition method, sputtering method, thermal plasma method, laser method; thermal decomposition method The metal particles can be obtained using a chemical wet method such as a chemical reduction method, an electrolysis method, an ultrasonic method, a laser ablation method, a supercritical fluid method, or a microwave synthesis method.

For example, in the vapor deposition method, fine particles are produced by contacting the above-mentioned heat-evaporated metal in a low vapor pressure liquid containing a dispersant under high vacuum.
Further, as one type of chemical reduction method, there is a method in which a metal oxide and a reducing agent are mixed in a solvent in the presence of a complexing agent and a protective colloid.

The complexing agent is a compound in which a donor atom of a ligand of the complexing agent and a metal ion or a metal atom are bonded to form a metal complex compound. Preferred examples of the donor atom include a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of the complexing agent in which the nitrogen atom is a donor atom include, but are not limited to, nitrogen-containing heterocyclic compounds such as amines, imidazole, and pyridine.
The protective colloid acts as a dispersion stabilizer for the purified metal particles. Specifically, it is a protein system such as gelatin, gum arabic, or casein; a natural polymer such as starch or dextrin; a hydroxyethyl cellulose; Cellulose type such as: hydrophilic synthetic polymers such as polyvinyl alcohol. Among these, protein-based protective colloids are preferable from the viewpoint of dispersion stability.
In addition to the above method, commercially available metal particles can be used as appropriate.

The average primary particle size of the metal particles may be appropriately set according to the use, but is usually set in the range of 1 to 500 nm. Especially, it is preferable that the average primary particle diameter of a metal particle is 5-200 nm from the point which is low viscosity, is excellent in a dispersibility and dispersion stability, and hardly produces a deposit.
In addition, the average particle diameter of the metal particles can be obtained by a method of directly measuring the size of primary particles from an electron micrograph. Specifically, the minor axis diameter and major axis diameter of each primary particle were measured, and the average was taken as the particle diameter of the particle. Next, for each of 100 or more particles, the volume (mass) of each particle was obtained by approximating a rectangular parallelepiped having the obtained particle size, and the volume average particle size was obtained and used as the average particle size. Note that the same result can be obtained regardless of whether the electron microscope is a transmission type (TEM), a scanning type (SEM), or a scanning transmission type (STEM).

  In the metal particle dispersion of the present invention, the content of the metal particles may be appropriately selected depending on the use, but from the viewpoint of dispersibility, it is 1 to 70% by mass with respect to the total amount of the metal particle dispersion. It is preferable that it is within a range of 5 to 50% by mass. In the present invention, when used in combination with a dispersant described later, the metal particles are excellent in dispersibility and dispersion stability even when the content of the metal particles is increased compared to the conventional case, and precipitates are generated. It can be difficult.

<Dispersant>
The dispersant used in the present invention has a structural unit represented by the following general formula (I) and a structural unit represented by the following general formula (II), and is represented by the above general formula (I). From the group consisting of at least a part of the nitrogen moiety contained in the structural unit, a halogenated hydrocarbon, an acidic phosphorus compound represented by the following general formula (V), and a sulfonic acid compound represented by the following general formula (VI) At least one selected is a graft copolymer in which a salt is formed.

(In general formula (I), A is a direct bond or a divalent linking group, R ¹ is a hydrogen atom or a methyl group, Q is a group represented by the following general formula (Ia), or a substituted group. Represents a nitrogen-containing heterocyclic group which may have a group and can form a salt.)

(In general formula (Ia), R ² and R ³ each independently represent a hydrocarbon group that may contain a hydrogen atom or a hetero atom, and R ² and R ³ may be the same or different from each other. May be.)

(In general formula (II), R ^{1 ′} is a hydrogen atom or a methyl group, L is a direct bond or a divalent linking group, and Polymer is represented by the following general formula (III) or general formula (IV). (Represents a polymer chain having at least one structural unit.)

(General formula (III) and the general formula (IV), ^{R 4} is a hydrogen atom or a methyl group, ^{R 5} is a hydrocarbon group, a cyano ^{group, - [CH (R 6)} -CH (R 7) - _{^{O] x -R 8, - [}} (CH 2) y -O] z -R 8, - [CO- (CH 2) y -O] z -R 8, -CO-O-R 9 or -O- It is a monovalent group represented by CO—R ^10. R ⁶ and R ⁷ are each independently a hydrogen atom or a methyl group.
R ⁸ is a hydrogen atom, a hydrocarbon group, a monovalent group represented by —CHO, —CH ₂ CHO, or —CH ₂ COOR ¹¹ , and R ⁹ is a hydrocarbon group, a cyano group, — [CH (R ⁶ ) —CH (R ⁷ ) —O] _x —R ⁸ , — [(CH ₂ ) _y —O] _z —R ⁸ , or — [CO— (CH ₂ ) _y —O] _z —R ⁸ A monovalent group. R ¹⁰ is an alkyl group having 1 to 18 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The hydrocarbon group may have a substituent.
m represents an integer of 1 to 5, and n and n ′ represent an integer of 5 to 200. x is an integer of 1 to 18, y is an integer of 1 to 5, and z is an integer of 1 to 18. )

(In General Formula (V) and General Formula (VI), R ^a and R ^{a ′} are each independently a hydrogen atom, a hydroxyl group, a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O]. _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^{a ″} is a monovalent group. R ^{a ″} represents a hydrocarbon group, — [ _{^{CH (R c) -CH (R}} d) -O] s -R e, - [(CH 2) t -O] u -R e, -C (R f) (R g) -C (R h) It is a monovalent group represented by (R ⁱ ) —OH or —CH ₂ —C (R ^j ) (R ^k ) —CH ₂ —OH.
R ^b is a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^b. It is a monovalent group represented by ^' . R ^{b ′} is a monovalent group represented by a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , or — [(CH ₂ ) _t —O] _u —R ^e. It is the basis of.
R ^c and R ^d are each independently a hydrogen atom or a methyl group, and R ^e is a monovalent group represented by a hydrogen atom, a hydrocarbon group, —CHO, —CH ₂ CHO, or —CH ₂ COOR ^1. And R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ^f , R ^g , R ^h , R ⁱ , R ^j and R ^k are each independently a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded to at least one of an ether bond and an ester bond. R ^f and R ^h may be bonded to each other to form a ring structure. When the above cyclic structure is formed, it may have a substituent R ⁿ , and R ⁿ is a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded by at least one of an ether bond and an ester bond. It is.
In R ^a , R ^{a ′} and R ^b , each hydrocarbon group may have a substituent.
s is an integer of 1 to 18, t is an integer of 1 to 5, and u is an integer of 1 to 18. )

  In the present invention, as the dispersant, the above general formula (I) having a nitrogen moiety forming a salt with at least one selected from the group consisting of halogenated hydrocarbons, specific acidic phosphorus compounds, and specific sulfonic acid compounds. ) Improves the dispersibility and dispersion stability of the metal particles. In addition, when the metal particle dispersion of the present invention is fired to form a metal film, the dispersant is easily decomposed by heating at the time of firing, and the resulting metal film has little residual dispersant, so that It is easy to develop desired functions such as sex. Further, since the viscosity of the metal fine particle dispersion can be reduced by using the above-mentioned dispersant, the metal particle dispersion of the present invention can also be suitably used as an ink for ink jet.

(Structural unit represented by general formula (I))
The graft copolymer used in the present invention has a structural unit represented by the general formula (I).
In general formula (I), A is a direct bond or a divalent linking group. The direct bond means that Q is directly bonded to a carbon atom without a linking group as in the following general formula (I-1).

(In general formula (I-1), R ¹ and Q are the same as in general formula (I).)

Examples of the divalent linking group in A include an alkylene group having 1 to 10 carbon atoms, an arylene group, a -CONH- group, a -COO- group, and an ether group having 1 to 10 carbon atoms (-R'-OR "- : R ′ and R ″ each independently represents an alkylene group) and combinations thereof.
Among these, from the viewpoint of dispersibility, A in the general formula (I) is preferably a direct bond or a divalent linking group containing a —CONH— group or a —COO— group.
For example, when A is a divalent linking group containing a —COO— group and Q is a group represented by the above general formula (Ia), the structural unit represented by the general formula (I) is represented by the following formula ( Examples include the structure represented by I-2).

(In General Formula (I-2), R ¹ is the same as in General Formula (I), R ² and R ³ are the same as in General Formula (Ia), and R ¹⁴ has 1 carbon atom. To 8 alkylene groups, — [CH (R ¹⁵ ) —CH (R ¹⁶ ) —O] _x —CH (R ¹⁵ ) —CH (R ¹⁶ ) — or — [(CH ₂ ) _y —O] _z — ( CH ₂ ) _y —, R ¹⁵ and R ¹⁶ are each independently a hydrogen atom or a methyl group, x is an integer of 1 to 18, y is an integer of 1 to 5, and z is an integer of 1 to 18. Represents.)

The alkylene group having 1 to 8 carbon atoms in R ¹⁴ in the general formula (I-2) may be linear or branched, and examples thereof include a methylene group, an ethylene group, a trimethylene group, a propylene group, Examples include various butylene groups, various pentylene groups, various hexylene groups, and various octylene groups.
R ¹⁵ and R ^{16 in} general formula (I-2) are each independently a hydrogen atom or a methyl group.
x is an integer of 1 to 18, preferably an integer of 1 to 4, more preferably an integer of 1 to 2, and y is an integer of 1 to 5, preferably an integer of 1 to 4, more preferably 2 or 3. is there. z is an integer of 1-18, preferably an integer of 1-4, more preferably an integer of 1-2.
R ^{14 in} formula (I-2) is preferably an alkylene group having 1 to 8 carbon atoms from the viewpoint of dispersibility, and among them, R ¹⁴ is a methylene group, an ethylene group, a propylene group, or a butylene group. Are more preferable, and a methylene group and an ethylene group are more preferable.

Examples of the hydrocarbon group in the hydrocarbon group that may contain a hetero atom of R ² and R ^{3 in} the general formula (Ia) include an alkyl group, an aralkyl group, and an aryl group.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2-ethylhexyl group, a cyclopentyl group, a cyclohexyl group, and the like. -18 are preferable, and among them, a methyl group or an ethyl group is more preferable.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a naphthylmethyl group, and a biphenylmethyl group. 7-20 are preferable and, as for carbon number of an aralkyl group, 7-14 are more preferable.
Examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, and a xylyl group. 6-24 are preferable and, as for carbon number of an aryl group, 6-12 are more preferable. The preferred carbon number does not include the carbon number of the substituent.
The hydrocarbon group containing a hetero atom has a structure in which the carbon atom in the hydrocarbon group is replaced with a hetero atom. Examples of the hetero atom that the hydrocarbon group may contain include an oxygen atom, a nitrogen atom, a sulfur atom, and a silicon atom.
Moreover, the hydrogen atom in a hydrocarbon group may be substituted by halogen atoms, such as a C1-C5 alkyl group, a fluorine atom, a chlorine atom, and a bromine atom.

Examples of the nitrogen-containing heterocyclic group capable of forming a salt that may have a substituent in Q include a 5- to 7-membered nitrogen-containing heterocyclic monocycle or a condensed ring thereof, Furthermore, it may have another hetero atom and may have a substituent. Moreover, the nitrogen-containing heterocyclic group may have aromaticity.
Specific examples of the nitrogen-containing heterocyclic compound forming the nitrogen-containing heterocyclic group include pyridine, piperidine, piperazine, morpholine, pyrrolidine, pyrroline, imidazole, pyrazole, triazole, tetrazole, and benzimidazole. Of these, nitrogen-containing heterocyclic compounds containing only nitrogen atoms as heteroatoms such as pyridine, piperidine, piperazine, and imidazole are preferred, and nitrogen-containing heterocyclic groups having aromaticity such as pyridine and imidazole are preferred. More preferred.

  Examples of the substituent that the nitrogen-containing heterocyclic group may have include, for example, a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, an aralkyl group, an aryl group, F, Cl, Br, and the like. These can be used in combination. Moreover, the substitution position of these substituents and the number of substituents are not particularly limited.

Examples of the structural unit represented by the general formula (I) include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, pentamethylpiperidyl (meta ) Nitrogen-containing (meth) acrylates such as acrylates; Nitrogen-containing vinyl monomers such as vinylimidazole and vinylpyridine; and structural units derived from acrylamide monomers such as dimethylaminopropylacrylamide. It is not limited.
The structural unit represented by the general formula (I) only needs to function as a site having an affinity with the metal particles, and may be composed of one kind, including two or more kinds of structural units. May be.

(Structural unit represented by general formula (II))
The graft copolymer has a structural unit represented by the general formula (II) containing a polymer chain in the side chain, so that the solvent affinity is good, and the dispersibility and dispersion stability of the metal particles are good. It will be something.

  In the general formula (II), L is a direct bond or a divalent linking group. The divalent linking group in L is not particularly limited as long as it can link an ethylenically unsaturated double bond and a polymer chain. Examples of the divalent linking group in L include an alkylene group, an alkylene group having a hydroxyl group, an arylene group, a —CONH— group, a —COO— group, a —NHCOO— group, an ether group (—O— group), and a thioether group. (—S— group), and combinations thereof. In the present invention, the direction of bonding of the divalent linking group is arbitrary. That is, when -CONH- is contained in the divalent linking group, -CO may be on the carbon atom side of the main chain and -NH may be on the polymer chain side of the side chain. On the carbon atom side, -CO may be a polymer chain side chain.

In the general formula (II), Polymer represents a polymer chain having at least one structural unit represented by the general formula (III) or the general formula (IV).
In formula (III), ^{R 4} is a hydrogen atom or a methyl group, ^{R 5} is a hydrocarbon group, a cyano ^{group, - [CH (R 6)} -CH (R 7) -O] x -R 8, - [ (CH ₂ ) _y —O] _z —R ⁸ , — [CO— (CH ₂ ) _y —O] _z —R ⁸ , —CO—O—R ⁹ or monovalent represented by —O—CO—R ¹⁰ It is the basis of.
The hydrocarbon group for R ⁵ is preferably an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aralkyl group, or an aryl group.
The alkyl group having 1 to 18 carbon atoms may be linear, branched, or cyclic. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2- Examples thereof include an ethylhexyl group, 2-ethoxyethyl group, cyclopentyl group, cyclohexyl group, bornyl group, isobornyl group, dicyclopentanyl group, adamantyl group, and lower alkyl group-substituted adamantyl group.
The alkenyl group having 2 to 18 carbon atoms may be linear, branched or cyclic. Examples of such an alkenyl group include a vinyl group, an allyl group, and a propenyl group. The position of the double bond of the alkenyl group is not limited, but from the viewpoint of the reactivity of the polymer obtained, it is preferable that there is a double bond at the terminal of the alkenyl group.

Examples of the aryl group in R ⁵ include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, and a xylyl group. 6-24 are preferable and, as for carbon number of an aryl group, 6-12 are more preferable.
Examples of the aralkyl group in R ⁵ include a benzyl group, a phenethyl group, a naphthylmethyl group, and a biphenylmethyl group. 7-20 are preferable and, as for carbon number of an aralkyl group, 7-14 are more preferable.

R ⁸ is a hydrogen atom or a monovalent group represented by an alkyl group having 1 to 18 carbon atoms, an aralkyl group, an aryl group, —CHO, —CH ₂ CHO, or —CH ₂ COOR ¹¹ , and R ⁹ is C1-C18 alkyl group, aralkyl group, aryl group, cyano group, — [CH (R ⁶ ) —CH (R ⁷ ) —O] _x —R ⁸ , — [(CH ₂ ) _y —O] _z It is a monovalent group represented by —R ⁸ or — [CO— (CH ₂ ) _y —O] _z —R ⁸ . R ¹⁰ is an alkyl group having 1 to 18 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
Of the R ⁸ and R ⁹ , the alkyl group having 1 to 18 carbon atoms, the aralkyl group, and the aryl group are as described for R ⁵ above.
The alkyl group in R ¹⁰ and R ¹¹ is as shown for R ⁵ above.
When R ⁵ , R ⁸ , R ⁹ , and R ¹⁰ are groups having an aromatic ring, the aromatic ring may further have a substituent. Examples of the substituent include linear, branched, and cyclic alkyl groups having 1 to 5 carbon atoms, and halogen atoms such as alkenyl groups, nitro groups, F, Cl, and Br.
The preferred carbon number does not include the carbon number of the substituent.
In the above R ⁵ and R ⁹ , x, y and z are as described in the above A.

Furthermore, the above R ⁵ , R ⁸ , R ⁹ and R ¹⁰ are within the range not impeding the dispersion performance of the graft copolymer, and further, alkoxy groups, hydroxyl groups, carboxyl groups, amino groups, epoxy groups, isocyanate groups. Or a substituent such as a hydrogen bond-forming group. Moreover, after synthesizing a graft copolymer having these substituents, a compound having a functional group that reacts with the substituent and a polymerizable group may be reacted to add a polymerizable group. For example, adding a polymerizable group by reacting a graft copolymer having a carboxyl group with glycidyl (meth) acrylate, or reacting a graft copolymer having an isocyanate group with hydroxyethyl (meth) acrylate. Can do.

  The polymer chain contained in the structural unit represented by the general formula (II) includes methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate among the above-described structural units. , Isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, Those having structural units derived from isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, styrene, α-methylstyrene, vinylcyclohexane and the like are preferable. However, it is not limited to these.

  In general formula (IV), m is an integer of 1-5, Preferably it is an integer of 2-5, More preferably, it is an integer of 4 or 5. The number of units n and n ′ of the polymer chain constituent units may be an integer of 5 to 200, and is not particularly limited, but is preferably in the range of 5 to 100.

In the present invention, as R ⁵ and R ⁹ , those having excellent solubility with a solvent described later are preferably used, and may be appropriately selected according to the solvent used for the metal particle dispersion. Specifically, for example, when the solvent is an ether alcohol acetate type, ether type, ester type or the like generally used as a solvent for the metal particle dispersion, a methyl group, an ethyl group, or an isobutyl group is used. Group, n-butyl group, 2-ethylhexyl group, benzyl group and the like are preferable.
Here, the reason for setting R ⁵ and R ⁹ in this way is that the structural unit containing R ⁵ and R ⁹ is soluble in the solvent, and is formed by the base portion of the monomer. This is because the dispersibility and stability of the metal particles can be made particularly excellent by the formation site having high adsorptivity to the metal particles.
Furthermore, R ⁵ and R ⁹ are preferably selected as appropriate in accordance with the use of the metal particle dispersion. For example, when the metal particle dispersion is fired and used, as R ⁵ and R ⁹ , a branched alkyl group (isopropyl, isobutyl, 2-ethylhexyl), a methyl group, an n-butyl group, or the like that is easily thermally decomposed. Is preferred. When the metal particle dispersion is fired and used, the branched alkyl group is preferably a branched alkyl group having 3 to 18 carbon atoms, and more preferably a branched alkyl group having 3 to 8 carbon atoms. preferable.
In addition, for example, when used for a functional film having heat ray shielding properties, the R ⁵ and R ⁹ are alicyclic alkyl groups (cyclohexyl, isobornyl, adamantyl) in consideration of transparency and heat resistance. Etc. are preferable.
Further, when a resin molded product containing a metal particle dispersion is used, it is preferable to have a skeleton similar to the resin used in combination. For example, when polymethyl methacrylate is used, as R ⁵ and R ⁹ described above, Is preferably a methyl group or the like.

  The polymer chain mass average molecular weight Mw in Polymer is preferably in the range of 500 to 15000, and more preferably in the range of 1000 to 8000. By being the said range, while being able to hold | maintain sufficient steric repulsion effect as a dispersing agent, the increase in the time required for dispersion | distribution of the metal particle by a steric effect can also be suppressed.

Further, as a guide, the polymer chain in Polymer preferably has a solubility at 23 ° C. of 50 (g / 100 g solvent) or more with respect to the solvent used in combination.
The solubility of the polymer chain can be based on the fact that the raw material into which the polymer chain is introduced when preparing the graft copolymer has the above-mentioned solubility. For example, when a polymerizable oligomer containing a polymer chain and a group having an ethylenically unsaturated double bond at its end is used to introduce a polymer chain into the graft copolymer, the polymerizable oligomer has the above-described solubility. Just do it. In addition, after a copolymer is formed with a monomer containing a group having an ethylenically unsaturated double bond, a polymer chain containing a reactive group capable of reacting with a reactive group contained in the copolymer is used. In the case of introducing a polymer chain, it is sufficient that the polymer chain containing the reactive group has the above-described solubility.

  The polymer chain may be a homopolymer or a copolymer. Moreover, the polymer chain contained in the structural unit represented by the general formula (II) may be used alone or in combination of two or more in the graft copolymer.

In the graft copolymer, the structural unit containing a nitrogen moiety represented by the general formula (I) is preferably contained in a proportion of 3 to 80% by mass, more preferably 5 to 50% by mass, 10-40 mass% is further more preferable. If the content of the structural unit containing a nitrogen moiety in the graft copolymer is within the above range, the adsorptivity to the metal particles by the salt forming site in the graft copolymer and the solvent by the polymer chain in the graft copolymer. The balance of solubility becomes appropriate, and excellent dispersibility and dispersion stability can be obtained.
In addition, the content rate of the said structural unit is computed from the preparation amount at the time of synthesize | combining the graft copolymer which has a structural unit represented by general formula (I).

  Moreover, the weight average molecular weight Mw of the graft copolymer is preferably in the range of 1000 to 100,000, more preferably in the range of 3000 to 30000, and further in the range of 5000 to 20000. preferable. By being the said range, a metal particle can be disperse | distributed uniformly.

  The weight average molecular weight Mw is a value measured by GPC (gel permeation chromatography). For the measurement, HLC-8120GPC manufactured by Tosoh Corporation was used, the elution solvent was N-methylpyrrolidone to which 0.01 mol / liter of lithium bromide was added, and polystyrene standards for calibration curves were Mw377400, 210500, 96000, 50400, 20650. , 10850, 5460, 2930, 1300, 580 (Easi PS-2 series manufactured by Polymer Laboratories) and Mw1090000 (manufactured by Tosoh Corp.), and TSK-GEL ALPHA-M × 2 (manufactured by Tosoh Corp.) It has been done.

  In the present invention, the graft copolymer is produced by producing a graft copolymer having the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II). The method is not particularly limited as long as it can be performed. For example, a nitrogen-containing monomer represented by the following general formula (I ′), a polymer chain having at least one structural unit represented by the general formula (III) or the general formula (IV), and ethylenic at the terminal Examples thereof include a method of producing a graft copolymer by containing a polymerizable oligomer composed of a group having an unsaturated double bond as a copolymerization component and copolymerizing it. If necessary, other monomers can also be used to produce a graft copolymer using a known polymerization means.

(In general formula (I ′), R ¹ , A and Q are the same as in general formula (I).)

Further, after the addition of the nitrogen-containing monomer represented by the general formula (I ′) and another monomer containing a group having an ethylenically unsaturated double bond to form a copolymer, the copolymer The polymer chain may be introduced using a polymer chain containing a reactive group capable of reacting with the reactive group contained therein. Specifically, for example, after synthesizing a copolymer having a substituent such as an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, or a hydrogen bond-forming group, a functional group that reacts with the substituent is added. The polymer chain may be introduced by reacting with the polymer chain contained therein.
For example, a polymer chain having a glycidyl group at the terminal is reacted with a copolymer having a carboxyl group at the side chain, or a polymer chain having a hydroxy group at the terminal is reacted with a copolymer having an isocyanate group at the side chain. Alternatively, polymer chains can be introduced.
In the above polymerization, additives generally used in the polymerization, for example, a polymerization initiator, a dispersion stabilizer, a chain transfer agent and the like may be used.

(Halogenated hydrocarbons, acidic phosphorus compounds, sulfonic acid compounds)
The dispersant of the present invention includes at least a part of the nitrogen moiety of the structural unit represented by the general formula (I), a halogenated hydrocarbon, an acidic phosphorus compound represented by the following general formula (V), and the following At least one selected from the group consisting of sulfonic acid compounds represented by the general formula (VI) is a graft copolymer in which a salt is formed.
In the present invention, at least one selected from the group consisting of halogenated hydrocarbons, acidic phosphorus compounds represented by the following general formula (V), and sulfonic acid compounds represented by the following general formula (VI) is salted: When used as a forming agent, the dispersant is excellent in dispersibility and stability of the metal particles, and when the metal particle dispersion of the present invention is fired to form a metal film, the dispersant is volatilized or decomposed during firing. Easy to do.

Examples of the halogenated hydrocarbon include those in which any one of a chlorine atom, a bromine atom and an iodine atom is substituted with a hydrogen atom of a saturated or unsaturated linear, branched or cyclic hydrocarbon. .
In addition, the halogenated hydrocarbon preferably has 1 to 30 carbon atoms, more preferably 1 to 25, and still more preferably 1 to 18.

  Among the halogenated hydrocarbons, examples of the halogenated alkyl include those having 1 to 18 carbon atoms, but are not particularly limited. Specifically, for example, methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, methyl iodide, ethyl iodide, n-butyl chloride, hexyl chloride, octyl chloride, dodecyl chloride, tetradecyl chloride, hexadecyl chloride, etc. Can be mentioned. Examples of the allyl halide include allyl chloride, allyl bromide, and allyl iodide. Further, examples of the aralkyl group of the halogenated aralkyl include those having 7 to 18 carbon atoms, but are not particularly limited. Specific examples include benzyl chloride, benzyl bromide, benzyl iodide, naphthylmethyl chloride, pyridylmethyl chloride, naphthylmethyl bromide, pyridylmethyl bromide and the like. Examples of the aryl halide include those having 6 to 18 carbon atoms, but are not particularly limited. Specifically, benzene chloride etc. are mentioned, for example.

Among these, from the viewpoint of enhancing the dispersibility of the metal particles, it is preferably at least one of allyl halide and aralkyl halide, and more preferably allyl halide.
Specifically, it is at least one selected from the group consisting of allyl chloride, allyl bromide, allyl iodide, benzyl chloride, benzyl bromide, and benzyl iodide, The generated salt-forming site is preferable because of its excellent adsorptivity to metal particles.

The acidic phosphorus compound used in the present invention is a compound represented by the general formula (V), and the sulfonic acid compound is a compound represented by the general formula (VI).
In the general formula (V) and general formula (VI), the hydrocarbon group in R ^a , R ^{a ′} , R ^{a ″} , R ^b , R ^{b ′} , and R ^e has 1 to 18 carbon atoms. An alkyl group, an alkenyl group having 2 to 18 carbon atoms, an aralkyl group, or an aryl group is preferable, and the alkyl group, aralkyl group, and aryl group having 1 to 18 carbon atoms are represented by R in the general formula (III). ⁵ can be used.
In the general formula (V) and the general formula (VI), the hydrocarbon group in R ^f , R ^g , R ^h , R ⁱ , R ^j , R ^k , R ^l , and R ⁿ has 1 to 1 carbon atoms. It is preferably an alkyl group having 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aralkyl group, or an aryl group, and the alkyl group, aralkyl group, and aryl group having 1 to 18 carbon atoms are also represented by the general formula (III). The same as R ^{5 in} FIG.
Among them, the alkyl group having 1 to 8 carbon atoms, the aralkyl group having 7 to 11 carbon atoms, and the aryl group having 6 to 12 carbon atoms have good dispersibility of the metal particles, and the metal particle dispersion is fired. The organic component is preferably used because it is difficult for the organic component to remain.
In R ^a , R ^{a ′} , R ^{a ″} , R ^b and R ^{b ′} , s is an integer of 1 to 18, t is an integer of 1 to 5, and u is an integer of 1 to 18. s is preferably an integer of 1 to 4, more preferably an integer of 1 to 2, and t is preferably an integer of 1 to 4, more preferably 2 or 3. u is preferably an integer of 1 to 4, more preferably an integer of 1 to 2.

R ^f , R ^g , R ^h , R ⁱ , R ^j and R ^k , and a group in which a hydrocarbon group in R ⁿ is bonded by at least one of an ether bond and an ester bond are -R'-O- R ″, —R ′ — (C═O) —O—R ″, or —R′—O— (C═O) —R ″ (R ′ and R ″ are a hydrocarbon group or a hydrocarbon group, Is a group represented by at least one of an ether bond and an ester bond. One group may have two or more ether bonds and ester bonds. When the hydrocarbon group is bonded with at least one of an ether bond and an ester bond, at least one becomes a divalent hydrocarbon group. In that case, an alkyl group having 1 to 18 carbon atoms, an aralkyl group, and an aryl group Each group becomes a divalent group of an alkylene group, an arylene group, and a combination thereof.

In the general formula (V), R ^f and R ^h are bonded to each other to form a ring structure, specifically, has a structure represented by the following general formula (V-1). Things.

(In General Formula (V-1), R ^a , R ^g , and R ⁱ are the same as those in General Formula (V). R ^m is a group in which R ^f and R ^h are bonded. Te, which may have a substituent R ^n.)

When R ^f and R ^h are bonded to form a ring structure, the number of carbon atoms forming the ring structure is preferably 5 to 8, more preferably 6, that is, a 6-membered ring. .

^{-C (R f) (R g} ) -C (R h) (R i) -OH, _{^{or, -CH 2 -C (R j)}} (R k) -CH 2 -OH , respectively, for example, phosphoric acid It can be obtained by reacting a monofunctional epoxy compound or a monofunctional oxetane compound with the acidic group (OH) of the group.

When the metal particle dispersion is used for the purpose of forming a metal film by firing, it is represented by the general formula (V) from the viewpoint of excellent dispersibility of the metal particles and low resistance of the metal film. In the acidic phosphorus compound, at least one of R ^a and R ^{a ′} is preferably at least one of a hydrogen atom and a hydroxyl group.

  The halogenated hydrocarbon, the acidic phosphorus compound represented by the following general formula (V), and the sulfonic acid compound represented by the following general formula (VI) can be used singly or in combination of two or more. .

  The content of at least one of the halogenated hydrocarbon, the acidic phosphorus compound represented by the following general formula (V), and the sulfonic acid compound represented by the following general formula (VI) in the dispersant used in the present invention is good. As long as the dispersion stability is exhibited, there is no particular limitation, but generally 0.05 to 2.0 molar equivalents relative to the nitrogen moiety contained in the structural unit represented by the general formula (I) From the viewpoint of improving the dispersion stability of the metal particles, it is preferably about 0.1, preferably 1.0 to 1.0 molar equivalent, more preferably 0.2 to 0.8 molar equivalent.

(Manufacture of dispersant)
In the present invention, as a method for producing a salt-type dispersant used as a dispersant, at least a part of a nitrogen site contained in the structural unit represented by the general formula (I) of the graft copolymer obtained above is used. , A halogenated hydrocarbon, an acidic phosphorus compound represented by the general formula (V), and at least one selected from the group consisting of the sulfonic acid compounds represented by the general formula (VI) formed a salt. There is no particular limitation as long as it is a method capable of producing a graft copolymer.
For example, the graft copolymer obtained above is dissolved or dispersed in a solvent described later, and then the halogenated hydrocarbon, the acidic phosphorus compound represented by the general formula (V) in the solvent, and the above It can be produced by adding at least one sulfonic acid compound represented by the general formula (VI), stirring, and heating if necessary.

  In the metal particle dispersion of the present invention, as the dispersant, the above graft copolymer may be used singly or in combination of two or more, and the content is the kind of metal particles used. Is appropriately set according to the above, but is usually in the range of 1 to 200 parts by weight, preferably 3 to 100 parts by weight, and 5 to 80 parts by weight with respect to 100 parts by weight of the metal particles. Is more preferable. When the content of the dispersant is within the above range, the metal particles can be uniformly dispersed, and the dispersion stability is excellent.

<Solvent>
In the metal particle dispersion of the present invention, the solvent is not particularly limited as long as it is an organic solvent that does not react with each component in the metal particle dispersion and can dissolve or disperse them. Specifically, alcohols such as methyl alcohol, ethyl alcohol, N-propyl alcohol, and isopropyl alcohol; ether alcohols such as methoxy alcohol, ethoxy alcohol, methoxyethoxyethanol, ethoxyethoxyethanol, and propylene glycol monomethyl ether; ethyl acetate, Esters such as butyl acetate, 3-methoxybutyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, and ethyl lactate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; methoxyethyl acetate, methoxypropyl acetate, methoxybutyl Acetate, ethoxyethyl acetate, ethyl cellosolve acetate, methoxyethoxyethyl acetate, pro Ether alcohol acetates such as lenglycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate; ethers such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, tetrahydrofuran; N, N-dimethylformamide Aprotic amides such as N, N-dimethylacetamide and N-methylpyrrolidone; lactones such as γ-butyrolactone; unsaturated hydrocarbons such as benzene, toluene, xylene and naphthalene; n-heptane and n-hexane And organic solvents such as saturated hydrocarbons such as n-octane.

Among these, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ether alcohols such as propylene glycol monomethyl ether; methoxyethyl acetate, ethoxyethyl acetate, ethyl cellosolve acetate, methoxyethoxyethyl acetate, ethoxyethoxyethyl acetate, propylene Ether alcohol acetates such as glycol monomethyl ether acetate; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, propylene glycol diethyl ether; 3-methoxybutyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl lactate Esters such as Etc. can be suitably used.
Among them, as the solvent used in the present invention, (MEK) methyl ethyl ketone, MIBK (methyl isobutyl ketone), MBA (3-methoxybutyl acetate), PGMEA (propylene glycol monomethyl ether acetate), DMDG (diethylene glycol dimethyl ether), BCA (diethylene glycol) Monobutyl ether acetate), diethylene glycol monoethyl ether acetate, diethylene glycol methyl ethyl ether, PGME (propylene glycol monomethyl ether) or a mixture thereof is preferable from the viewpoint of solubility of the dispersant and applicability.

  The content of the solvent in the metal particle dispersion of the present invention is not particularly limited as long as it can uniformly dissolve or disperse each component of the metal particle dispersion. In the present invention, the solid content in the metal particle dispersion is preferably in the range of 5 to 70% by mass, more preferably in the range of 10 to 50% by mass. By being the said range, it can be set as the viscosity suitable for application | coating.

<Other ingredients>
The metal particle dispersion of the present invention may contain other components as necessary within a range not impairing the effects of the present invention.
Examples of other components include complexing agents, protective colloids, reducing agents, surfactants for improving wettability, silane coupling agents for improving adhesion, antifoaming agents, repellency inhibitors, and antioxidants. , Anti-aggregation agents, ultraviolet absorbers and the like.

<Method for producing metal particle dispersion>
In the present invention, the method for producing the metal particle dispersion may be any method that can disperse the metal particles satisfactorily, and can be appropriately selected from conventionally known methods. Specifically, for example, the dispersing agent is mixed and stirred in the solvent to prepare a dispersing agent solution, and then the dispersing agent solution is mixed with metal particles and other components as necessary. A metal particle dispersion can be prepared by dispersing using a stirrer or a disperser.

<Use of metal particle dispersion>
Since the metal particle dispersion of the present invention is excellent in dispersibility and dispersion stability, and the precipitation of metal particles is also suppressed, it can be suitably used for conventionally known applications. The metal particle dispersion of the present invention is used, for example, as a conductive material, a material that imparts metallic luster, an antibacterial material, a material that imparts heat ray shielding, a material that imparts antistatic properties, a fluorescent material, and the like. Furthermore, the metal particle dispersion of the present invention is particularly suitable for use in forming a metal film by firing, because even if the metal particle dispersion is fired at a lower temperature than in the past, the resulting metal film has little remaining organic components. be able to.

[Goods]
The article according to the present invention includes a coating film, a molded body, or a sintered film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention.

  The article according to the present invention is a high-quality article having a uniform coating film or molded body with reduced aggregation and unevenness of metal particles by using the metal particle dispersion having good dispersibility according to the present invention. Can be obtained. Moreover, when the sintered film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention is obtained by firing, a high-quality article including a metal film with little remaining organic components can be obtained. it can.

Examples of the article containing the coating film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention typically include an embodiment including a substrate serving as a support for the coating film. As one aspect, there may be mentioned an article taking the form of a substrate including a coating film of a metal particle dispersion or a composition containing the metal particle dispersion according to the present invention on a substrate. The coating film of the composition containing the metal particle dispersion includes a cured coating film when the composition contains a light and / or thermosetting resin.
Moreover, as an article including the sintered film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention, typically, an embodiment including a base material that becomes a support of the sintered film can be given.
Here, the coating film and the sintered film may be not only a continuous layer but also an island-like discontinuous layer, and include a state in which metal particles are discontinuously supported on a certain base material.

The article taking the form of the substrate according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of an article of the present invention. An article 100 is a sintered body formed by firing a metal particle dispersion or a composition containing a metal particle dispersion on a substrate 1. It has a conjunctiva 2.
FIG. 2 is a schematic cross-sectional view showing another example of the article of the present invention. The article 100 has a coating film 10 on which a metal particle 4 is supported by a thin film 3 on a base material 1.
FIG. 3 is a schematic cross-sectional view showing another example of the article of the present invention. The article 100 has a coating film 10 containing metal particles 6 in a matrix 5 on a substrate 1. .

The base material used in the embodiment including the base material is not particularly limited and may be appropriately selected from conventionally known base materials according to the application. For example, a resin base material and a glass base material are mentioned. A glass substrate is preferably used as the substrate to be a support for the sintered film. However, since the metal particle dispersion according to the present invention can be sintered at a lower temperature than conventional, the conventional sintered film can be used. On the other hand, even a resin base material that has been difficult to apply can be suitably used. Among these, the resin base material is preferably a base material having excellent heat resistance, and specific examples include a polyimide resin and a polyamide resin.
The shape of the base material may be appropriately selected depending on the application, and may be a flat plate or a curved surface. In the case of using a base material on a flat plate, the thickness of the base material may be appropriately set according to the application, and may be, for example, about 25 μm to 100 mm.

Examples of the article including the coating film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention include a heat ray shielding film and an antistatic film, but are not limited thereto. Absent.
Further, the sintered film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention, that is, the sintered film formed by firing the coating film of the metal particle dispersion or the composition containing the metal particle dispersion. Examples of the articles containing include, but are not limited to, wiring boards, conductive films, electrodes, photoelectric conversion semiconductor films, and the like.
About structures other than the said coating film or sintered film of these articles | goods, a conventionally well-known structure can be selected suitably and can be used.

On the other hand, as an article including the molded article of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention, there is typically an aspect that does not include a base material to be a support.
For example, resin moldings and resin fibers containing a metal particle dispersion as an antibacterial agent, coloring material, reinforcing material, etc., and antibacterial articles, design articles, and the like can be given.

  The constituent components contained in the composition containing the metal particle dispersion can be, for example, the thin film 3, the matrix 5, or the matrix of the molded body in the coating film 10. What is necessary is just to select and employ | adopt an ingredient suitably.

As a structural component contained in the composition containing a metal particle dispersion, an acrylic (co) polymer is mentioned, for example. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) ) Acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene, 2 -A polymer or copolymer obtained by polymerizing one or more monomers selected from the group consisting of hydroxylethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, and (meth) acrylic acid.
For the purpose of forming a sintered film, an acrylic (co) polymer obtained by polymerizing a monomer having a branched alkyl group such as isopropyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate or the like as a polymerization component is preferable. An acrylic copolymer obtained by polymerizing a monomer having an alkyl group and a monomer having an acid value such as methacrylic acid as a polymerization component is more preferable.
These are merely examples, and the constituent components contained in the composition containing the metal particle dispersion may be appropriately selected from known constituent components in each article and are not limited to the above.

In addition, in each article, the configurations and components other than the coating film, the molded body, or the sintered film of the metal particle dispersion or the composition containing the metal particle dispersion according to the present invention are also known configurations and configurations in each article. What is necessary is just to select and employ | adopt an ingredient suitably.
Specifically, for example, in the case of a heat ray shielding film, a structure in which a cured film of a composition containing the metal particle dispersion and the photocurable resin according to the present invention is arranged on a substrate such as a resin substrate is mentioned. It is done. As the resin base material and the photocurable resin, a resin base material and a photocurable resin conventionally used for heat ray shielding films can be appropriately selected and used.

<Production method>
The method for producing an article is obtained by, for example, applying the metal particle dispersion or the composition containing the metal particle dispersion on a base material or another functional layer on the base material to form a coating film. be able to. Moreover, the said coating film can be baked as needed and can be used as a sintered film.
The method for producing a sintered film of the present invention includes a step of applying a composition (coating liquid) containing a metal particle dispersion for forming a sintered film on a substrate to form a coating film, and firing the coating film. Process.

  As a method of applying the metal particle dispersion or the composition containing the metal particle dispersion, a conventionally known method may be appropriately selected. Examples of the method include gravure printing, screen printing, spray coating, die coating, spin coating, comma coating, bar coating, knife coating, offset printing, flexographic printing, ink jet printing, and dispenser printing. Among these, gravure printing, flexographic printing, screen printing, and ink jet printing are preferable because fine patterning can be performed. In particular, since the metal particle dispersion of the present invention is excellent in dispersibility, it is suitable for inkjet printing because clogging or ejection bending does not occur in inkjet ejection nozzles.

  The obtained coating film may be dried by a conventionally known method. Although the film thickness after drying may be suitably adjusted according to a use, it is the range of 0.01-100 micrometers normally, Preferably, it is 0.1-50 micrometers.

  When the coating film is baked to form a sintered film, a conventionally known baking method may be used. For example, a method of raising the temperature to a temperature at which metal particles are fired, a method using surface wave plasma generated by application of microwave energy, and the like can be mentioned.

  Moreover, what is necessary is just to select a conventionally well-known method suitably as the method of manufacturing the molded object of the composition containing the said metal particle dispersion. For example, as a molding method in the case of using a resin as a matrix, injection molding, blow molding, vacuum molding, pressure molding and the like can be exemplified.

  Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.

(Synthesis Example 1 Production of copper particles)
64 g of cupric oxide and 5.1 g of gelatin were added to 650 mL of pure water and mixed to prepare a mixed solution. The pH of the mixture was adjusted to 10 using 15% aqueous ammonia, and then heated from room temperature to 90 ° C. over 20 minutes. After raising the temperature, a mixture of 6.4 g of a 1% mercaptoacetic acid solution and 75 g of 80% hydrazine monohydrate in 150 mL of pure water was added as a complexing agent while stirring. Reaction with dicopper produced copper particles. Then, copper particles were obtained by filtering and washing and drying. When the obtained copper particles were observed with a scanning transmission electron microscope (STEM), the average primary particle size was 50 nm.

(Synthesis Example 2 Synthesis of Macromonomer MM-1)
A reactor equipped with a condenser, addition funnel, nitrogen inlet, mechanical stirrer, and digital thermometer was charged with 80.0 parts by mass of propylene glycol monomethyl ether acetate (abbreviated as PGMEA), and the temperature was maintained while stirring under a nitrogen stream. Warmed to 90 ° C. 50.0 parts by weight of methyl methacrylate, 15.0 parts by weight of methacrylate-n-butyl, 15.0 parts by weight of benzyl methacrylate, 20.0 parts by weight of 2-ethoxyethyl methacrylate, 4.0 parts by weight of mercaptoethanol, A mixed solution of 30 parts by mass of PGMEA and 1.0 part by mass of α, α′-azobisisobutyronitrile (abbreviation AIBN) was added dropwise over 1.5 hours, followed by further reaction for 3 hours. Next, the nitrogen stream was stopped, the reaction solution was cooled to 80 ° C., Karenz MOI (manufactured by Showa Denko KK) 8.74 parts by mass, dibutyltin dilaurate 0.125 parts by mass, p-methoxyphenol 0.125 The 49.5 mass% solution of macromonomer MM-1 was obtained by adding a mass part and 10 mass parts of PGMEA, and stirring for 3 hours. When the obtained macromonomer MM-1 was confirmed by GPC (gel permeation chromatography) under the conditions of N-methylpyrrolidone, 0.01 mol / L lithium bromide added / polystyrene standard, the mass average molecular weight (Mw 4040, number average molecular weight (Mn) 1930, molecular weight distribution (Mw / Mn) was 2.09.

(Synthesis Example 3 Synthesis of Macromonomer MM-2)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 90 ° C. while stirring under a nitrogen stream. A mixed solution of 100.0 parts by mass of methyl methacrylate, 4.0 parts by mass of mercaptoethanol, 30 parts by mass of PGMEA, and 1.0 part by mass of AIBN was added dropwise over 1.5 hours, and the reaction was further performed for 3 hours. Next, the nitrogen stream was stopped and the reaction solution was cooled to 80 ° C., and Karenz MOI 8.74 parts by mass, dibutyltin dilaurate 0.125 parts by mass, p-methoxyphenol 0.125 parts by mass, and PGMEA 10 parts by mass Were added and stirred for 3 hours to obtain a 49.8% by mass solution of macromonomer MM-2. When the obtained macromonomer MM-2 was confirmed by GPC (gel permeation chromatography) under the conditions of N-methylpyrrolidone, 0.01 mol / L lithium bromide added / polystyrene standard, the mass average molecular weight (Mw 4130, number average molecular weight (Mn) 1940, molecular weight distribution (Mw / Mn) was 2.13.

(Synthesis Example 4 Synthesis of Graft Copolymer GP-1)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 85 ° C. while stirring under a nitrogen stream. 67.33 parts by mass of the macromonomer MM-1 solution of Synthesis Example 2 (33.33 parts by mass of effective solid content), 16.67 parts by mass of 2- (dimethylamino) ethyl methacrylate (abbreviation DMA), n-dodecyl mercaptan 1 .24 parts by mass, PGMEA 20.0 parts by mass, AIBN 0.5 part by mass mixed solution mixed solution was dropped over 1.5 hours, heated and stirred for 3 hours, then AIBN 0.10 parts by mass, PGMEA 10.0 parts by mass The mixed solution was added dropwise over 10 minutes, and further aged at the same temperature for 1 hour to obtain a 26.0% by mass solution of the graft copolymer GP-1. As a result of GPC measurement, the obtained graft copolymer GP-1 had a mass average molecular weight (Mw) of 11510, a number average molecular weight (Mn) of 4730, and a molecular weight distribution (Mw / Mn) of 2.43.

(Synthesis Example 5 Synthesis of Graft Copolymer GP-2)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 85 ° C. while stirring under a nitrogen stream. 66.93 parts by mass of macromonomer MM-2 solution of Synthesis Example 3 (effective solid content 33.33 parts by mass), DMA 16.67 parts by mass, n-dodecyl mercaptan 1.24 parts by mass, PGMEA 20.0 parts by mass, AIBN 0. After 5 parts by mass of the mixed solution mixed solution was added dropwise over 1.5 hours and heated and stirred for 3 hours, a mixed solution of AIBN 0.10 parts by mass and PGMEA 10.0 parts by mass was added dropwise over 10 minutes, and the same temperature. Was then aged for 1 hour to obtain a 26.2 mass% solution of graft copolymer GP-2. As a result of GPC measurement, the obtained graft copolymer GP-2 had a mass average molecular weight (Mw) of 11230, a number average molecular weight (Mn) of 4350, and a molecular weight distribution (Mw / Mn) of 2.58.

(Synthesis Example 6 Synthesis of Graft Copolymer GP-3)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 85 ° C. while stirring under a nitrogen stream. 50.50 parts by mass of the macromonomer MM-1 solution of Synthesis Example 2 (25.00 parts by mass of effective solid content), 11.9 parts by mass of Plaxel FA-10L (manufactured by Daicel Chemical Industries, Ltd. 10 mol of caprolactone in hydroxyethyl acrylate) % Solution effective solid content 8.33 parts by mass), DMA 16.67 parts by mass, n-dodecyl mercaptan 1.24 parts by mass, PGMEA 30.0 parts by mass, AIBN 0.5 parts by mass over 1.5 hours After 3 hours of heating and stirring, a mixture of AIBN 0.10 parts by mass and PGMEA 10.0 parts by mass was added dropwise over 10 minutes, and further aged at the same temperature for 1 hour, so that the graft copolymer GP- 3 of 25.8 mass% solution was obtained. As a result of GPC measurement, the obtained graft copolymer GP-3 had a mass average molecular weight (Mw) of 12700, a number average molecular weight (Mn) of 4880, and a molecular weight distribution (Mw / Mn) of 2.60.

(Synthesis Example 7 Synthesis of Organic Phosphonate Compound 1)
In a reactor equipped with a condenser, addition funnel, nitrogen inlet, mechanical stirrer, digital thermometer, 142.61 parts by mass of diethylene glycol ethyl methyl ether (EMDG) and phenylphosphonic acid (trade name: PPA, Nissan Chemical Co., Ltd.) (Made) 50.00 mass parts and p-methoxyphenol 0.10 mass part were prepared, and it heated to temperature 120 degreeC, stirring under nitrogen stream. Organic phosphonic acid monoester in which 44.96 parts by mass of glycidyl methacrylate (GMA) is added dropwise over 30 minutes and heated and stirred for 2 hours so that half of the divalent acidic group of PPA is esterified with the epoxy group of GMA A 40.0 mass% solution of organic phosphonate ester compound 1 (PPA-GMA) containing the compound was obtained. The progress of the esterification reaction was confirmed by acid value measurement, and the composition ratio of the product was confirmed by ³¹ P-NMR measurement. The acid value was 190 mgKOH / g, and the composition ratio was 55% for the organic phosphonic acid monoester compound, 23% for the organic phosphonic acid diester compound, and 22% for PPA.

(Production Example 1 Preparation of Dispersant Solution A)
In a 100 mL eggplant flask, 35.49 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (9.23 parts by mass of effective solid content) was dissolved in 13.74 parts by mass of PGMEA, and phenylphosphonic acid ( Dispersant solution A by adding 0.77 parts by mass (trade name: PPA, manufactured by Nissan Chemical Co., Ltd.) (0.25 molar equivalent to the tertiary amino group of the graft copolymer) and stirring at 40 ° C. for 30 minutes. (20 mass% solid content) was prepared. At this time, the amino group of the graft copolymer is salt-formed with an acid / base reaction with phenylphosphonic acid.

(Production Example 2 Preparation of Dispersant Solution B)
In Production Example 1, 13.90 parts by mass of PGMEA, 35.27 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (9.17 parts by mass of effective solid content), phenylphosphinic acid 0 instead of phenylphosphonic acid Dispersant solution B was prepared in the same manner as in Production Example 1 except that .83 parts by mass (0.3 molar equivalents relative to the amino group of the graft copolymer) was used. At this time, the amino group of the graft copolymer is salt-formed by an acid-base reaction with phenylphosphinic acid.

(Production Example 3 Preparation of Dispersant Solution C)
In Production Example 1, 14.14 parts by mass of PGMEA, 34.95 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content: 9.09 parts by mass), and benzenesulfonic acid 0 instead of phenylphosphonic acid Dispersant solution C was prepared in the same manner as in Production Example 1 except that .91 parts by mass (0.3 molar equivalent relative to the amino group of the graft copolymer) was used. At this time, the amino group of the graft copolymer is salt-formed by an acid-base reaction with benzenesulfonic acid.

(Production Example 4 Preparation of Dispersant Solution D)
In Production Example 1, 12.73 parts by mass of PGMEA, 36.86 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content: 9.58 parts by mass), and 0.7 mg of phosphonic acid instead of phenylphosphonic acid. Dispersant solution D was prepared in the same manner as in Production Example 1 except that 42 parts by mass (0.25 molar equivalent relative to the amino group of the graft copolymer) was used. At this time, the amino group of the graft copolymer is salt-formed by an acid-base reaction with phosphonic acid.

(Production Example 5 Preparation of Dispersant Solution E)
In Production Example 1, 12.29 parts by mass of PGMEA, 36.91 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content 9.60 parts by mass), and 50 mg of phosphinic acid instead of phenylphosphonic acid Dispersant solution in the same manner as in Production Example 1 except that 0.80 part by weight of an aqueous solution (0.40 part by weight of effective solid content, 0.3 molar equivalent to the amino group of the graft copolymer) was used. E was prepared. At this time, the amino group of the graft copolymer is salt-formed by phosphinic acid and an acid-base reaction.

(Production Example 6 Preparation of Dispersant Solution F)
In Production Example 1, 13.70 parts by mass of PGMEA, 32.30 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content 8.40 parts by mass), instead of phenylphosphonic acid, Synthesis Example 7 Except for using 4.00 parts by mass of the obtained organic phosphonic acid ester compound 1 (PPA-GMA) (effective solid content 1.60 parts by mass, 0.3 molar equivalent to the amino group of the graft copolymer). A dispersant solution F was prepared in the same manner as in Production Example 1. At this time, the amino group of the graft copolymer is salt-formed with the organic phosphonic acid ester compound 1 by an acid-base reaction.

(Production Example 7 Preparation of Dispersant Solution G)
In Production Example 2, instead of 14.17 parts by mass of PGMEA and the graft copolymer GP-1 solution of Synthesis Example 4, 35.00 parts by mass of the graft copolymer GP-2 solution of Synthesis Example 5 (effective solid content of 9. A dispersant solution G was prepared in the same manner as in Production Example 2 except that 17 parts by mass) was used. At this time, the amino group of the graft copolymer is salt-formed by an acid-base reaction with phenylphosphinic acid.

(Production Example 8 Preparation of Dispersant Solution H)
In Production Example 2, instead of 13.62 parts by mass of PGMEA and the graft copolymer GP-1 solution of Synthesis Example 4, 35.55 parts by mass of the graft copolymer GP-3 solution of Synthesis Example 6 (effective solid content 9. A dispersant solution H was prepared in the same manner as in Production Example 2, except that 17 parts by mass) was used. At this time, the amino group of the graft copolymer is salt-formed by an acid-base reaction with phenylphosphinic acid.

(Production Example 9 Preparation of Dispersant Solution I)
In a 100 mL eggplant flask, 35.60 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content 9.25 parts by mass) was dissolved in 13.66 parts by mass of PGMEA. 75 parts by mass (0.3 molar equivalent to the tertiary amino group of the graft copolymer) was added, and the mixture was stirred at 120 ° C. for 2 hours to prepare Dispersant Solution I (solid content 20% by mass). At this time, the amino group of the graft copolymer is salted with benzyl chloride by a quaternization reaction.

(Production Example 10 Preparation of Dispersant Solution J)
In Production Example 9, 12.86 parts by mass of PGMEA, 36.68 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content: 9.54 parts by mass), instead of benzyl chloride, 0.46 allyl chloride Dispersant solution J was prepared in the same manner as in Production Example 9 except that mass parts (0.3 molar equivalents relative to the amino group of the graft copolymer) were used. At this time, the amino group of the graft copolymer is salted with allyl chloride by a quaternization reaction.

(Production Example 11 Preparation of Dispersant Solution K)
In Production Example 1, 13.57 parts by mass of PGMEA, 35.71 parts by mass of the graft copolymer GP-1 solution of Synthesis Example 4 (effective solid content 9.29 parts by mass), allyl bromide 0 instead of phenylphosphonic acid Dispersant solution K was prepared in the same manner as in Production Example 1 except that .71 parts by mass (0.3 molar equivalents relative to the amino group of the graft copolymer) was used. At this time, the amino group of the graft copolymer is salted with allyl bromide by a quaternization reaction.

Example 1 Preparation of Metal Particle Dispersion A
40.0 parts by mass of the copper particles obtained in Synthesis Example 1, 15.0 parts by mass of the dispersant solution A obtained in Production Example 1 (3.0 parts by mass of effective solids), and 45.0 parts by mass of PGMEA are mixed. In a paint shaker (manufactured by Asada Tekko), dispersion was performed with 2 mm zirconia beads for 1 hour as a preliminary dispersion and further with 0.1 mm zirconia beads as a main dispersion for 4 hours to obtain metal particle dispersion A of Example 1.

(Preparation of Examples 2-11 Metal Particle Dispersions BK)
In Example 1, instead of the dispersant solution A, the metals of Examples 2 to 11 were used in the same manner as in Example 1 except that the dispersant solutions B to K obtained in Production Examples 2 to 11 were used. Particle dispersions B to K were obtained.

(Preparation of Comparative Example 1 Metal Particle Dispersion X1)
In Example 1, instead of the dispersant solution A, 11.54 parts by mass (effective solid content: 3.0 parts by mass) of the graft copolymer GP-1 solution of Synthesis Example 4 in which no salt was formed was used. Except that it was 46 mass parts, it carried out similarly to Example 1, and obtained the metal-particle dispersion X1 of the comparative example 1.

(Comparative Example 2 Preparation of Metal Particle Dispersion X2)
Comparative Example 2 was performed in the same manner as in Example 1, except that 3.0 parts by mass of Solsperse 71000 (manufactured by Nippon Lubrizol Co., Ltd.) and 57.0 parts by mass of PGMEA were used in place of the dispersant solution A. A metal particle dispersion X2 was obtained.

(Comparative Example 3 Preparation of Metal Particle Dispersion X3)
In Example 1, instead of Dispersant Solution A, BYK-111 (manufactured by BYK-Chemie) 3.0 parts by mass and PGMEA 57.0 parts by mass were used in the same manner as Example 1 except that Comparative Example 3 Metal particle dispersion X3 was obtained.

(Comparative Example 4 Preparation of Metal Particle Dispersion X4)
In Example 1, instead of the dispersant solution A, BYK-161 (manufactured by Big Chemie) 10.0 parts by mass (effective solid content 3.0 parts by mass) and PGMEA 50.0 parts by mass were used. In the same manner as in Example 1, a metal particle dispersion X4 of Comparative Example 4 was obtained.

(Comparative Example 5 Preparation of Metal Particle Dispersion X5)
Comparative Example 5 was carried out in the same manner as in Example 1, except that 3.0 parts by mass of Azisper PB821 (manufactured by Ajinomoto Fine Techno Co., Ltd.) and 57.0 parts by mass of PGMEA were used in place of the dispersant solution A. Metal particle dispersion X5 was obtained.

(Evaluation)
<Dispersibility evaluation>
As an evaluation of the dispersibility of the metal particles, the average particle diameter and shear viscosity of the metal particles in the metal particle dispersions obtained in each of Examples and Comparative Examples were measured. The average particle size is measured using “Nanotrack particle size distribution meter UPA-EX150” manufactured by Nikkiso Co., Ltd., and the viscosity is measured using “Rheometer MCR301” manufactured by Anton Paar. Shear viscosity when the shear rate is 60 rpm. Was measured. The results are shown in Table 1.

<Evaluation of sediment>
The metal particle dispersions obtained in each Example and Comparative Example were allowed to stand for 1 week in the refrigerator, and the sediment in the metal fine particle dispersion after standing was visually observed. The results are shown in Table 1.
Without sediment, it can be said that the dispersion stability is excellent.

<Sintering evaluation>
(1) Production of Conductive Substrate The metal particle dispersion obtained in each Example and Comparative Example was placed on a glass substrate (trade name: OA-10G, manufactured by Nippon Electric Glass Co., Ltd., thickness 0.7 m) with a wire bar. And dried at 80 ° C. for 15 minutes to form a coating film having a thickness of 2 μm. The obtained coating film was baked for 30 minutes in a mixed gas atmosphere of 300 ° C. and 3 volume% hydrogen / 97 volume% nitrogen to obtain a conductive substrate.

(2) Measurement of sheet resistance value Substrates of Examples 1 to 11 and Comparative Examples 1 to 5 obtained in (1) above using a surface resistance meter ("Loresta GP" manufactured by Dia Instruments, PSP type probe) The four probe was brought into contact with the sintered film, and the sheet resistance value was measured by the four probe method. The results are shown in Table 1.
If the sheet resistance value is low, it can be said that the low-temperature sinterability is excellent and the remaining organic components are small. The upper limit of sheet resistance measured by this measurement method was 10 ⁸ Ω / □.

From the results of Table 1, the dispersant has a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II), and is represented by the general formula (I). A graft copolymer in which at least a part of a nitrogen moiety contained in a unit and at least one selected from the group consisting of a halogenated hydrocarbon, a specific acidic phosphorus compound, and a specific sulfonic acid compound form a salt. It was clarified that the metal particle dispersions of Examples 1 to 11 used were excellent in dispersibility and dispersion stability, did not cause sediment, and were suitable for low-temperature sintering. The metal particle dispersion of Comparative Example 1 using a dispersant having a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II) but not forming a salt, A sediment was formed and the dispersion stability was poor. In addition, in the metal particle dispersions of Comparative Examples 2 to 5 using other commercially available dispersants, sediment was generated and the dispersion stability was poor. Further, Comparative Examples 2 to 5 were found to have high sheet resistance values and poor low-temperature sinterability.

(Synthesis Example 8 Production of silver particles)
To a mixed solution of 50 g of silver nitrate and 200 mL of pure water, a solution mixed with 5 g of polydimethyl 2-methylaminoethyl methacrylate (mass average molecular weight 2000) and 50 mL of pure water was added and reacted with silver nitrate for 1 hour to produce silver. Particles were generated. Then, silver particles were obtained by filtering and washing and drying. When the obtained silver particles were observed with a scanning transmission electron microscope (STEM), the average primary particle size was 40 nm.

(Example 12: Preparation of metal particle dispersion L)
10.0 parts by mass of the silver particles obtained in Synthesis Example 8, 30.0 parts by mass of the dispersant solution B obtained in Production Example 2 (6.0 mass parts of effective solid content), and 60.0 parts by mass of PGMEA are mixed. In a paint shaker, the dispersion was performed with 2 mm zirconia beads for 1 hour as a preliminary dispersion and further with 0.1 mm zirconia beads for 8 hours as a main dispersion to obtain a metal particle dispersion L of Example 12.

(Example 13: Preparation of metal particle dispersion M)
In Example 12, metal particles of Example 13 were used in the same manner as Example 12 except that molybdenum particles (manufactured by Sigma-Aldrich, 100 nm or less) were used instead of silver particles, and the main dispersion time was 6 hours. Dispersion M was obtained.

Example 14 Preparation of Metal Particle Dispersion N
In Example 12, instead of silver particles, alumina particles (manufactured by Sigma-Aldrich, 100 nm or less) were used, and the same dispersion time was set to 2 hours. Dispersion N was obtained.

Example 15 Preparation of Metal Particle Dispersion O
10.0 parts by mass of ATO particles (tin-doped antimony oxide particles, “T-1-20L” manufactured by Mitsubishi Materials Corporation, average particle size 20 nm), 15.0 parts by mass of the dispersant solution B obtained in Production Example 2 (effective solid content) 3.0 parts by weight) and 75.0 parts by weight of PGMEA were mixed and dispersed for 1 hour with 2 mm zirconia beads as a pre-dispersion in a paint shaker, and further for 24 hours with 0.1 mm zirconia beads as a main dispersion. A particle dispersion O was obtained.

(Example 16: Preparation of metal particle dispersion P)
In Example 15, a metal particle dispersion P of Example 16 was obtained in the same manner as in Example 15 except that the dispersant solution K of Production Example 11 was used instead of the dispersant solution B.

Example 17 Preparation of Metal Particle Dispersion Q
In Example 15, in place of ATO particles, ITO particles (tin-doped indium oxide particles, “Nanotech ITO-R”, manufactured by CEI Kasei Co., Ltd., average particle size 30 nm) were used, except that this dispersion time was 12 hours. In the same manner as in Example 15, a metal particle dispersion Q of Example 17 was obtained.

(Evaluation)
<Dispersibility evaluation>
As an evaluation of the dispersibility of the metal particles, the average particle diameter and shear viscosity of the metal particles in the metal particle dispersions obtained in Examples 12 to 17 were measured. The average particle size is measured using “Nanotrack particle size distribution meter UPA-EX150” manufactured by Nikkiso Co., Ltd., and the viscosity is measured using “Rheometer MCR301” manufactured by Anton Paar. Shear viscosity when the shear rate is 60 rpm. Was measured. The results are shown in Table 2.

<Evaluation of sediment>
The metal particle dispersions obtained in Examples 12 to 17 were allowed to stand for 1 week by refrigeration, and the sediment in the metal fine particle dispersions after standing was visually observed. The results are shown in Table 2.
Without sediment, it can be said that the dispersion stability is excellent.

  As a result of Table 2, the dispersant has a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II), and is represented by the general formula (I). Graft copolymer in which at least a part of the nitrogen moiety contained in the structural unit and at least one selected from the group consisting of a halogenated hydrocarbon, a specific acidic phosphorus compound, and a specific sulfonic acid compound form a salt The metal particle dispersion using No. 1 was excellent in dispersibility and dispersion stability even when the metal particles were other than copper, and no precipitate was formed.

(Example 18 Production of heat ray absorbing film)
The ink was prepared by mixing 4.81 parts by mass of the metal particle dispersion Q of Example 17, 1.78 parts by mass of pentaerythritol triacrylate, and 0.10 parts by mass of Irgacure 814 (BASF). The ink is applied on a PET film so as to have a thickness of 10 μm, dried in an oven at 70 ° C. for 3 minutes, and then cured by irradiating 300 mJ / cm ² of ultraviolet rays with an ultraviolet exposure machine in a nitrogen atmosphere. A membrane was prepared.

(Evaluation)
<Transmittance measurement>
The transmittance | permeability of the 300-3000 nm wavelength range was measured for the cured coating film of Example 18 using the spectrophotometer (Shimadzu Corporation UV3100).
Table 3 shows the measurement results of infrared transmittance (transmittance at 1200 nm) and visible light transmittance (transmittance at 650 nm).

(Synthesis Example 9 Synthesis of Macromonomer MM-3)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 90 ° C. while stirring under a nitrogen stream. A mixed solution of 100.0 parts by mass of isobutyl methacrylate, 4.0 parts by mass of mercaptoethanol, 30.0 parts by mass of PGMEA, and 1.0 parts by mass of AIBN was added dropwise over 1.5 hours, and the reaction was further performed for 3 hours. Next, the nitrogen stream was stopped and the reaction solution was cooled to 80 ° C., and 8.74 parts by weight of Karenz MOI, 0.125 parts by weight of dibutyltin dilaurate, 0.125 parts by weight of p-methoxyphenol, and PGMEA 10.0. The 50.0 mass% solution of macromonomer MM-3 was obtained by adding 3 mass parts and stirring for 3 hours. When the obtained macromonomer MM-3 was confirmed by GPC (gel permeation chromatography) under the conditions of N-methylpyrrolidone, 0.01 mol / L lithium bromide added / polystyrene standard, the mass average molecular weight (Mw 3720, number average molecular weight (Mn) 1737, molecular weight distribution (Mw / Mn) was 2.14.

(Synthesis Example 10 Synthesis of Graft Copolymer GP-4)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 85 ° C. while stirring under a nitrogen stream. 66.66 parts by mass of the macromonomer MM-3 solution of Synthesis Example 9 (33.33 parts by mass of effective solid content), 16.67 parts by mass of 2- (dimethylamino) ethyl methacrylate (abbreviation DMA), n-dodecyl mercaptan 1 .24 parts by mass, PGMEA 25.0 parts by mass, AIBN 0.5 part by mass mixed solution mixed solution was dropped over 1.5 hours, heated and stirred for 3 hours, then AIBN 0.10 parts by mass, PGMEA 10.0 parts by mass The mixed solution was added dropwise over 10 minutes, and further aged at the same temperature for 1 hour to obtain a 25.2% by mass solution of the graft copolymer GP-4. As a result of GPC measurement, the obtained graft copolymer GP-4 was found to have a mass average molecular weight (Mw) of 13063, a number average molecular weight (Mn) of 5259, and a molecular weight distribution (Mw / Mn) of 2.42.

(Synthesis Example 11 Synthesis of Graft Copolymer GP-5)
A reactor equipped with a condenser, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 80.0 parts by mass of PGMEA and heated to 85 ° C. while stirring under a nitrogen stream. Macromonomer MM-3 solution 90.0 parts by mass (effective solid content 45.0 parts by mass), DMA 5.0 parts by mass, n-dodecyl mercaptan 1.24 parts by mass, PGMEA 10.0 parts by mass, AIBN 0. After 5 parts by mass of the mixed solution mixed solution was added dropwise over 1.5 hours and heated and stirred for 3 hours, a mixed solution of AIBN 0.10 parts by mass and PGMEA 10.0 parts by mass was added dropwise over 10 minutes, and the same temperature. Was then aged for 1 hour to obtain a 27.0 mass% solution of graft copolymer GP-5. As a result of GPC measurement, the obtained graft copolymer GP-5 was mass average molecular weight (Mw) 12761, number average molecular weight (Mn) 5482, and molecular weight distribution (Mw / Mn) was 2.33.

(Production Example 12 Preparation of Dispersant Solution L)
In a 100 mL eggplant flask, 33.16 parts by mass of the graft copolymer GP-4 solution of Synthesis Example 10 (8.36 parts by mass of effective solid content) was dissolved in 11.19 parts by mass of PGMEA, and allyl bromide was 0. .64 parts by mass (0.3 molar equivalent to the tertiary amino group of the graft copolymer) was added, and the mixture was stirred at 40 ° C. for 30 minutes to prepare a dispersant solution L (solid content 20% by mass). At this time, the amino group of the graft copolymer GP-4 is salted with allyl bromide by a quaternization reaction.

(Production Example 13 Preparation of Dispersant Solution M)
In Production Example 12, 13.41 parts by mass of PGMEA, 30.95 parts by mass of the graft copolymer GP-5 solution of Synthesis Example 11 (effective solid content 8.36 parts by mass), 0.64 parts by mass of allyl bromide (for both grafts) A dispersant solution M (solid content: 20% by mass) was prepared in the same manner as in Production Example 1 except that 1.0 molar equivalent) was used with respect to the amino group of the polymer. At this time, the amino group of the graft copolymer GP-5 is salted with allyl bromide by a quaternization reaction.

(Synthesis Example 12 Production of CuInGaS Particles)
Bis (2,4-pentanedionato) copper (II) 5.11 g, Tris (2,4-pentandionato) indium (III) 6.47 g, Tris (2,4-pentandionato) gallium (III) 3.04 g was charged with 50 ml of oleylamine and heated at 150 ° C. for 10 minutes while stirring under a nitrogen stream. After heating to 285 ° C., 2.45 g of sulfur dissolved in 60 ml of oleylamine was injected and reacted for 30 minutes. It returned to room temperature, the product was precipitated by adding isopropyl alcohol (IPA), the product was isolate | separated by centrifugation operation, and the CuInGaS particle | grains were obtained by drying.

(Example 19: Preparation of metal particle dispersion R)
The CuInGaS particles obtained in Synthesis Example 12, the dispersant solution L15.0 parts by mass (effective solid content of 3.0 parts by mass) obtained in Production Example 12, and 75.0 parts by mass of methyl isobutyl ketone (MIBK) were mixed. Then, the dispersion was performed with a paint shaker (manufactured by Asada Tekko Co., Ltd.) as a pre-dispersion for 1 hour with 2 mm zirconia beads, and further as a main dispersion with 0.1 mm zirconia beads for 1 hour.

Example 20 Preparation of Metal Particle Dispersion S
In Example 19, a metal particle dispersion S of Example 20 was obtained in the same manner as in Example 19 except that the dispersant solution M obtained in Production Example 13 was used instead of the dispersant solution L. .

Example 21 Preparation of Metal Particle Dispersion T
Copper sulfide (manufactured by Alfa Aesar) 4.3 parts by mass, indium sulfide (manufactured by Alfa Aesar) 4.4 parts by mass, gallium sulfide (manufactured by Aldrich) 1.3 parts by mass, dispersant obtained in Production Example 12 Solution L 15.0 parts by mass (effective solid content 3.0 parts by mass) and MIBK 75.0 parts by mass were mixed, and pre-dispersed with a paint shaker with 2 mm zirconia beads for 1 hour, and further with 0.1 mm zirconia beads as main dispersion. Dispersion was performed for 3 hours to obtain a metal particle dispersion T of Example 21.

(Comparative Example 6 Preparation of Metal Particle Dispersion U)
In Example 19, a metal particle dispersion U of Comparative Example 6 was obtained in the same manner as in Example 19 except that 3.0 parts by mass of oleylamine and 97.0 parts by mass of MIBK were used instead of the dispersant solution L. .

(Comparative Example 7 Preparation of Metal Particle Dispersion V)
In Example 19, the metal of Comparative Example 7 was used in the same manner as in Example 19 except that instead of the dispersant solution L, 3.0 parts by mass of PB822 (manufactured by Ajinomoto Fine Techno Co., Ltd.) and 97.0 parts by mass of MIBK were used. A particle dispersion V was obtained.

(Comparative Example 8 Preparation of Metal Particle Dispersion W)
In Example 19, the metal of Comparative Example 8 was used in the same manner as in Example 19, except that 3.0 parts by mass of BYK-180 (manufactured by Big Chemie) and 97.0 parts by mass of MIBK were used instead of the dispersant solution L. A particle dispersion W was obtained.

(Evaluation)
<Dispersion stability evaluation>
As evaluation of the dispersion stability of metal particles, the metal particle dispersions obtained in Examples 19 to 21 and Comparative Examples 6 to 8 were allowed to stand at room temperature, and the number of days until deposition of metal particles started was measured.
The results are shown in Table 4.

<Residual carbon content evaluation>
(1) Preparation of CuInGaS Thin Films The metal particle dispersions obtained in Examples 19 to 21 and Comparative Examples 6 to 8 were used as glass substrates (trade name: OA-10G, manufactured by Nippon Electric Glass Co., Ltd., thickness 0.7 m). A film was formed on a spin coater and dried at 80 ° C. for 1 minute to form a coating film having a thickness of 500 nm. The obtained coating film was baked at 350 ° C. in the air for 5 minutes to obtain a CuInGaS thin film.

(2) Residual carbon amount (C / Cu) measurement SEM-EDX apparatus (Hitachi High-Tech "Energy dispersive X-ray analyzer Quantax70"), Examples 19 to 21 obtained in the above (1) and Comparative Examples The Cu atom concentration number and the C atom concentration number of the thin films of 6 to 8 were measured, and the residual carbon amount was calculated from the C atom concentration number / Cu atom concentration number, and the results are shown in Table 4.
It can be said that the smaller the value of the residual carbon amount, the less the organic component remains in the film.

DESCRIPTION OF SYMBOLS 1 Base material 2 Metal film 3 Thin film 4 Metal particle 5 Coating film 10 Metal-containing layer 100 Substrate

Claims (7)

Containing metal particles, a dispersant, and a solvent,
The metal particles are metal particles including one or more selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, and germanium. Yes, and
The dispersant has a structural unit represented by the following general formula (I) and a structural unit represented by the following general formula (II), and is included in the structural unit represented by the general formula (I). At least a part of the nitrogen moiety selected from the group consisting of a halogenated hydrocarbon, an acidic phosphorus compound represented by the following general formula (V), and a sulfonic acid compound represented by the following general formula (VI) A metal particle dispersion, wherein one kind is a graft copolymer in which a salt is formed.
(In general formula (I), A is a direct bond or a divalent linking group, R ¹ is a hydrogen atom or a methyl group, Q is a group represented by the following general formula (Ia), or a substituted group. Represents a nitrogen-containing heterocyclic group which may have a group and can form a salt.)
(In general formula (Ia), R ² and R ³ each independently represent a hydrocarbon group that may contain a hydrogen atom or a hetero atom, and R ² and R ³ may be the same or different from each other. May be.)
(In general formula (II), R ^{1 ′} is a hydrogen atom or a methyl group, L is a direct bond or a divalent linking group, and Polymer is represented by the following general formula (III) or general formula (IV). (Represents a polymer chain having at least one structural unit.)
(General formula (III) and the general formula (IV), ^{R 4} is a hydrogen atom or a methyl group, ^{R 5} is a hydrocarbon group, a cyano ^{group, - [CH (R 6)} -CH (R 7) - _{^{O] x -R 8, - [}} (CH 2) y -O] z -R 8, - [CO- (CH 2) y -O] z -R 8, -CO-O-R 9 or -O- It is a monovalent group represented by CO—R ^10. R ⁶ and R ⁷ are each independently a hydrogen atom or a methyl group.
R ⁸ is a hydrogen atom, a hydrocarbon group, a monovalent group represented by —CHO, —CH ₂ CHO, or —CH ₂ COOR ¹¹ , and R ⁹ is a hydrocarbon group, a cyano group, — [CH (R ⁶ ) —CH (R ⁷ ) —O] _x —R ⁸ , — [(CH ₂ ) _y —O] _z —R ⁸ , or — [CO— (CH ₂ ) _y —O] _z —R ⁸ A monovalent group. R ¹⁰ is an alkyl group having 1 to 18 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The hydrocarbon group may have a substituent.
m represents an integer of 1 to 5, and n and n ′ represent an integer of 5 to 200. x is an integer of 1 to 18, y is an integer of 1 to 5, and z is an integer of 1 to 18. )
(In General Formula (V) and General Formula (VI), R ^a and R ^{a ′} are each independently a hydrogen atom, a hydroxyl group, a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O]. _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^{a ″} is a monovalent group. R ^{a ″} represents a hydrocarbon group, — [ _{^{CH (R c) -CH (R}} d) -O] s -R e, - [(CH 2) t -O] u -R e, -C (R f) (R g) -C (R h) It is a monovalent group represented by (R ⁱ ) —OH or —CH ₂ —C (R ^j ) (R ^k ) —CH ₂ —OH.
R ^b is a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^b. It is a monovalent group represented by ^' . R ^{b ′} is a monovalent group represented by a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , or — [(CH ₂ ) _t —O] _u —R ^e. It is the basis of.
R ^c and R ^d are each independently a hydrogen atom or a methyl group, and R ^e is a monovalent group represented by a hydrogen atom, a hydrocarbon group, —CHO, —CH ₂ CHO, or —CH ₂ COOR ^1. And R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ^f , R ^g , R ^h , R ⁱ , R ^j and R ^k are each independently a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded to at least one of an ether bond and an ester bond. R ^f and R ^h may be bonded to each other to form a ring structure. When the above cyclic structure is formed, it may have a substituent R ⁿ , and R ⁿ is a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded by at least one of an ether bond and an ester bond. It is.
In R ^a , R ^{a ′} and R ^b , each hydrocarbon group may have a substituent.
s is an integer of 1 to 18, t is an integer of 1 to 5, and u is an integer of 1 to 18. )   The metal particle dispersion according to claim 1, wherein the average primary particle diameter of the metal particles is 5 to 200 nm.   The article containing the coating film, the molded object, or the sintered film of the composition containing the metal particle dispersion or metal particle dispersion according to claim 1 or 2. Containing metal particles, a dispersant, and a solvent,
The metal particles include one or more metals selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, lanthanum, indium, gallium, zinc, and germanium. Particles, and
The dispersant has a structural unit represented by the following general formula (I) and a structural unit represented by the following general formula (II), and is included in the structural unit represented by the general formula (I). At least a part of the nitrogen moiety selected from the group consisting of a halogenated hydrocarbon, an acidic phosphorus compound represented by the following general formula (V), and a sulfonic acid compound represented by the following general formula (VI) A metal particle dispersion for forming a sintered film, wherein one kind is a graft copolymer in which a salt is formed.
(In general formula (I), A is a direct bond or a divalent linking group, R ¹ is a hydrogen atom or a methyl group, Q is a group represented by the following general formula (Ia), or a substituted group. Represents a nitrogen-containing heterocyclic group which may have a group and can form a salt.)
(In general formula (Ia), R ² and R ³ each independently represent a hydrocarbon group that may contain a hydrogen atom or a hetero atom, and R ² and R ³ may be the same or different from each other. May be.)
(In General Formula (II), R ^{1 ′} is a hydrogen atom or a methyl group, L is a direct bond or a divalent linking group, and Polymer is at least one structural unit represented by the following General Formula (III). Represents a polymer chain having.)
(In General Formula (III), R ⁴ is a hydrogen atom or a methyl group, and R ⁵ is a branched alkyl group having 3 to 18 carbon atoms or a monovalent group represented by —CO—O—R ⁹ . R ⁹ is a branched alkyl group having 3 to 18 carbon atoms, and n is an integer of 5 to 200.)
(In General Formula (V) and General Formula (VI), R ^a and R ^{a ′} are each independently a hydrogen atom, a hydroxyl group, a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O]. _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^{a ″} is a monovalent group. R ^{a ″} represents a hydrocarbon group, — [ _{^{CH (R c) -CH (R}} d) -O] s -R e, - [(CH 2) t -O] u -R e, -C (R f) (R g) -C (R h) It is a monovalent group represented by (R ⁱ ) —OH or —CH ₂ —C (R ^j ) (R ^k ) —CH ₂ —OH.
R ^b is a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , — [(CH ₂ ) _t —O] _u —R ^e , or —O—R ^b. It is a monovalent group represented by ^' . R ^{b ′} is a monovalent group represented by a hydrocarbon group, — [CH (R ^c ) —CH (R ^d ) —O] _s —R ^e , or — [(CH ₂ ) _t —O] _u —R ^e. It is the basis of.
R ^c and R ^d are each independently a hydrogen atom or a methyl group, and R ^e is a monovalent group represented by a hydrogen atom, a hydrocarbon group, —CHO, —CH ₂ CHO, or —CH ₂ COOR ^1. And R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ^f , R ^g , R ^h , R ⁱ , R ^j and R ^k are each independently a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded to at least one of an ether bond and an ester bond. R ^f and R ^h may be bonded to each other to form a ring structure. When the above cyclic structure is formed, it may have a substituent R ⁿ , and R ⁿ is a hydrogen atom, a hydrocarbon group, or a group in which a hydrocarbon group is bonded by at least one of an ether bond and an ester bond. It is.
In R ^a , R ^{a ′} and R ^b , each hydrocarbon group may have a substituent.
s is an integer of 1 to 18, t is an integer of 1 to 5, and u is an integer of 1 to 18. ) The metal particle dispersion for forming a sintered film according to claim 4, wherein the metal particles contain a metal compound containing the following (i), (ii) and (iii).
(I) copper,
(Ii) one or more selected from the group consisting of indium, gallium, zinc, tin, and aluminum,
(Iii) one or more selected from the group consisting of sulfur, selenium, and tellurium   A sintered film obtained by firing a coating film of a composition containing the metal particle dispersion for forming a sintered film according to claim 4 or 5.   A process comprising a step of applying the composition containing the metal particle dispersion for forming a sintered film according to claim 4 or 5 on a substrate to form a coating film, and a process of firing the coating film. Manufacturing method of conjunctiva.